diff --git a/pretix_servicefees/apps.py b/pretix_servicefees/apps.py
index 6dbf801..a7b3c99 100644
--- a/pretix_servicefees/apps.py
+++ b/pretix_servicefees/apps.py
@@ -1,22 +1,23 @@
 from django.apps import AppConfig
 from django.utils.translation import gettext_lazy
+
 from . import __version__
 
 
 class PluginApp(AppConfig):
-    name = 'pretix_servicefees'
-    verbose_name = 'Service Fees'
+    name = "pretix_servicefees"
+    verbose_name = "Service Fees"
 
     class PretixPluginMeta:
-        name = gettext_lazy('Service Fees')
-        author = 'Raphael Michel'
-        category = 'FEATURE'
-        description = gettext_lazy('This plugin allows to charge a service fee on all non-free orders.')
+        name = gettext_lazy("Service Fees")
+        author = "Raphael Michel"
+        category = "FEATURE"
+        description = gettext_lazy(
+            "This plugin allows to charge a service fee on all non-free orders."
+        )
         visible = True
         version = __version__
         compatibility = "pretix>=4.16.0"
 
     def ready(self):
         from . import signals  # NOQA
-
-
diff --git a/pretix_servicefees/signals.py b/pretix_servicefees/signals.py
index 031471b..3d60d8d 100644
--- a/pretix_servicefees/signals.py
+++ b/pretix_servicefees/signals.py
@@ -18,64 +18,83 @@ from pretix.presale.views import get_cart
 from pretix.presale.views.cart import cart_session
 
 
-@receiver(nav_event_settings, dispatch_uid='service_fee_nav_settings')
+@receiver(nav_event_settings, dispatch_uid="service_fee_nav_settings")
 def navbar_settings(sender, request, **kwargs):
     url = resolve(request.path_info)
-    return [{
-        'label': _('Service Fee'),
-        'url': reverse('plugins:pretix_servicefees:settings', kwargs={
-            'event': request.event.slug,
-            'organizer': request.organizer.slug,
-        }),
-        'active': url.namespace == 'plugins:pretix_servicefees' and url.url_name.startswith('settings'),
-    }]
+    return [
+        {
+            "label": _("Service Fee"),
+            "url": reverse(
+                "plugins:pretix_servicefees:settings",
+                kwargs={
+                    "event": request.event.slug,
+                    "organizer": request.organizer.slug,
+                },
+            ),
+            "active": url.namespace == "plugins:pretix_servicefees"
+            and url.url_name.startswith("settings"),
+        }
+    ]
 
 
-def get_fees(event, total, invoice_address, mod='', request=None, positions=[], gift_cards=None, payment_requests=None):
+def get_fees(
+    event,
+    total,
+    invoice_address,
+    mod="",
+    request=None,
+    positions=[],
+    gift_cards=None,
+    payment_requests=None,
+):
     if request is not None and not positions:
         positions = get_cart(request)
 
-    skip_free = event.settings.get('service_fee_skip_free', as_type=bool)
+    skip_free = event.settings.get("service_fee_skip_free", as_type=bool)
     if skip_free:
-        positions = [pos for pos in positions if pos.price != Decimal('0.00')]
+        positions = [pos for pos in positions if pos.price != Decimal("0.00")]
 
-    skip_addons = event.settings.get('service_fee_skip_addons', as_type=bool)
+    skip_addons = event.settings.get("service_fee_skip_addons", as_type=bool)
     if skip_addons:
         positions = [pos for pos in positions if not pos.addon_to_id]
 
-    skip_non_admission = event.settings.get('service_fee_skip_non_admission', as_type=bool)
+    skip_non_admission = event.settings.get(
+        "service_fee_skip_non_admission", as_type=bool
+    )
     if skip_non_admission:
         positions = [pos for pos in positions if pos.item.admission]
 
-    fee_per_ticket = event.settings.get('service_fee_per_ticket' + mod, as_type=Decimal)
+    fee_per_ticket = event.settings.get("service_fee_per_ticket" + mod, as_type=Decimal)
     if mod and fee_per_ticket is None:
-        fee_per_ticket = event.settings.get('service_fee_per_ticket', as_type=Decimal)
+        fee_per_ticket = event.settings.get("service_fee_per_ticket", as_type=Decimal)
 
-    fee_abs = event.settings.get('service_fee_abs' + mod, as_type=Decimal)
+    fee_abs = event.settings.get("service_fee_abs" + mod, as_type=Decimal)
     if mod and fee_abs is None:
-        fee_abs = event.settings.get('service_fee_abs', as_type=Decimal)
+        fee_abs = event.settings.get("service_fee_abs", as_type=Decimal)
 
-    fee_percent = event.settings.get('service_fee_percent' + mod, as_type=Decimal)
+    fee_percent = event.settings.get("service_fee_percent" + mod, as_type=Decimal)
     if mod and fee_percent is None:
-        fee_percent = event.settings.get('service_fee_percent', as_type=Decimal)
+        fee_percent = event.settings.get("service_fee_percent", as_type=Decimal)
 
     fee_per_ticket = Decimal("0") if fee_per_ticket is None else fee_per_ticket
     fee_abs = Decimal("0") if fee_abs is None else fee_abs
     fee_percent = Decimal("0") if fee_percent is None else fee_percent
 
-    if event.settings.get('service_fee_skip_if_gift_card', as_type=bool):
+    if event.settings.get("service_fee_skip_if_gift_card", as_type=bool):
         if payment_requests is not None:
             for p in payment_requests:
-                if p['provider'] == 'giftcard':
-                    total = max(0, total - Decimal(p['max_value'] or '0'))
+                if p["provider"] == "giftcard":
+                    total = max(0, total - Decimal(p["max_value"] or "0"))
 
         else:
             # pretix pre 4.15
             gift_cards = gift_cards or []
             if request:
                 cs = cart_session(request)
-                if cs.get('gift_cards'):
-                    gift_cards = event.organizer.accepted_gift_cards.filter(pk__in=cs.get('gift_cards'), currency=event.currency)
+                if cs.get("gift_cards"):
+                    gift_cards = event.organizer.accepted_gift_cards.filter(
+                        pk__in=cs.get("gift_cards"), currency=event.currency
+                    )
             summed = 0
             for gc in gift_cards:
                 fval = Decimal(gc.value)  # TODO: don't require an extra query
@@ -90,16 +109,21 @@ def get_fees(event, total, invoice_address, mod='', request=None, positions=[],
     # payment provider.
     if payment_requests is not None:
         for p in payment_requests:
-            if event.settings.get(f'service_fee_skip_if_{p["provider"]}', default=False, as_type=bool):
-                total = max(0, total - Decimal(p['max_value'] or '0'))
+            if event.settings.get(
+                f'service_fee_skip_if_{p["provider"]}', default=False, as_type=bool
+            ):
+                total = max(0, total - Decimal(p["max_value"] or "0"))
 
-    if (fee_per_ticket or fee_abs or fee_percent) and total != Decimal('0.00'):
+    if (fee_per_ticket or fee_abs or fee_percent) and total != Decimal("0.00"):
         tax_rule_zero = TaxRule.zero()
-        fee = round_decimal(fee_abs + total * (fee_percent / 100) + len(positions) * fee_per_ticket, event.currency)
-        split_taxes = event.settings.get('service_fee_split_taxes', as_type=bool)
+        fee = round_decimal(
+            fee_abs + total * (fee_percent / 100) + len(positions) * fee_per_ticket,
+            event.currency,
+        )
+        split_taxes = event.settings.get("service_fee_split_taxes", as_type=bool)
         if split_taxes:
             # split taxes based on products ordered
-            d = defaultdict(lambda: Decimal('0.00'))
+            d = defaultdict(lambda: Decimal("0.00"))
             for p in positions:
                 if isinstance(p, CartPosition):
                     tr = p.item.tax_rule
@@ -110,16 +134,24 @@ def get_fees(event, total, invoice_address, mod='', request=None, positions=[],
             base_values = sorted([tuple(t) for t in d.items()], key=lambda t: t[0].rate)
             sum_base = sum(t[1] for t in base_values)
             if sum_base:
-                fee_values = [(t[0], round_decimal(fee * t[1] / sum_base, event.currency))
-                              for t in base_values]
+                fee_values = [
+                    (t[0], round_decimal(fee * t[1] / sum_base, event.currency))
+                    for t in base_values
+                ]
                 sum_fee = sum(t[1] for t in fee_values)
 
                 # If there are rounding differences, we fix them up, but always leaning to the benefit of the tax
                 # authorities
                 if sum_fee > fee:
-                    fee_values[0] = (fee_values[0][0], fee_values[0][1] + (fee - sum_fee))
+                    fee_values[0] = (
+                        fee_values[0][0],
+                        fee_values[0][1] + (fee - sum_fee),
+                    )
                 elif sum_fee < fee:
-                    fee_values[-1] = (fee_values[-1][0], fee_values[-1][1] + (fee - sum_fee))
+                    fee_values[-1] = (
+                        fee_values[-1][0],
+                        fee_values[-1][1] + (fee - sum_fee),
+                    )
             else:
                 fee_values = [(event.settings.tax_rate_default or tax_rule_zero, fee)]
 
@@ -129,15 +161,19 @@ def get_fees(event, total, invoice_address, mod='', request=None, positions=[],
         fees = []
         for tax_rule, price in fee_values:
             tax_rule = tax_rule or tax_rule_zero
-            tax = tax_rule.tax(price, invoice_address=invoice_address, base_price_is='gross')
-            fees.append(OrderFee(
-                fee_type=OrderFee.FEE_TYPE_SERVICE,
-                internal_type='',
-                value=price,
-                tax_rate=tax.rate,
-                tax_value=tax.tax,
-                tax_rule=tax_rule
-            ))
+            tax = tax_rule.tax(
+                price, invoice_address=invoice_address, base_price_is="gross"
+            )
+            fees.append(
+                OrderFee(
+                    fee_type=OrderFee.FEE_TYPE_SERVICE,
+                    internal_type="",
+                    value=price,
+                    tax_rate=tax.rate,
+                    tax_value=tax.tax,
+                    tax_rule=tax_rule,
+                )
+            )
         return fees
 
     return []
@@ -145,7 +181,7 @@ def get_fees(event, total, invoice_address, mod='', request=None, positions=[],
 
 @receiver(fee_calculation_for_cart, dispatch_uid="service_fee_calc_cart")
 def cart_fee(sender: Event, request: HttpRequest, invoice_address, total, **kwargs):
-    mod = ''
+    mod = ""
     try:
         from pretix_resellers.utils import (
             ResellerException, get_reseller_and_user,
@@ -161,48 +197,70 @@ def cart_fee(sender: Event, request: HttpRequest, invoice_address, total, **kwar
         except ResellerException:
             pass
         else:
-            mod = '_resellers'
-    return get_fees(sender, total, invoice_address, mod, request, payment_requests=kwargs.get('payment_requests'))
+            mod = "_resellers"
+    return get_fees(
+        sender,
+        total,
+        invoice_address,
+        mod,
+        request,
+        payment_requests=kwargs.get("payment_requests"),
+    )
 
 
 @receiver(order_fee_calculation, dispatch_uid="service_fee_calc_order")
-def order_fee(sender: Event, positions, invoice_address, total, meta_info, gift_cards, **kwargs):
-    mod = ''
-    if meta_info.get('servicefees_reseller_id'):
-        mod = '_resellers'
+def order_fee(
+    sender: Event, positions, invoice_address, total, meta_info, gift_cards, **kwargs
+):
+    mod = ""
+    if meta_info.get("servicefees_reseller_id"):
+        mod = "_resellers"
         try:
             from pretix_resellers.models import Reseller
         except ImportError:
             pass
         else:
-            r = Reseller.objects.get(pk=meta_info.get('servicefees_reseller_id'))
+            r = Reseller.objects.get(pk=meta_info.get("servicefees_reseller_id"))
             config = r.configs.get(organizer_id=sender.organizer_id)
             if config.skip_default_service_fees:
                 return []
 
-    return get_fees(sender, total, invoice_address, mod, positions=positions, gift_cards=gift_cards,
-                    payment_requests=kwargs.get('payment_requests'))
+    return get_fees(
+        sender,
+        total,
+        invoice_address,
+        mod,
+        positions=positions,
+        gift_cards=gift_cards,
+        payment_requests=kwargs.get("payment_requests"),
+    )
 
 
 @receiver(front_page_top, dispatch_uid="service_fee_front_page_top")
 def front_page_top_recv(sender: Event, **kwargs):
     fees = []
-    fee_per_ticket = sender.settings.get('service_fee_per_ticket', as_type=Decimal)
+    fee_per_ticket = sender.settings.get("service_fee_per_ticket", as_type=Decimal)
     if fee_per_ticket:
-        fees = fees + ["{} {}".format(money_filter(fee_per_ticket, sender.currency), gettext('per ticket'))]
+        fees = fees + [
+            "{} {}".format(
+                money_filter(fee_per_ticket, sender.currency), gettext("per ticket")
+            )
+        ]
 
-    fee_abs = sender.settings.get('service_fee_abs', as_type=Decimal)
+    fee_abs = sender.settings.get("service_fee_abs", as_type=Decimal)
     if fee_abs:
-        fees = fees + ["{} {}".format(money_filter(fee_abs, sender.currency), gettext('per order'))]
+        fees = fees + [
+            "{} {}".format(money_filter(fee_abs, sender.currency), gettext("per order"))
+        ]
 
-    fee_percent = sender.settings.get('service_fee_percent', as_type=Decimal)
+    fee_percent = sender.settings.get("service_fee_percent", as_type=Decimal)
     if fee_percent:
-        fees = fees + ['{} % {}'.format(fee_percent, gettext('per order'))]
+        fees = fees + ["{} % {}".format(fee_percent, gettext("per order"))]
 
     if fee_per_ticket or fee_abs or fee_percent:
-        return '<p>%s</p>' % gettext('A service fee of {} will be added to the order total.').format(
-            ' {} '.format(gettext('plus')).join(fees)
-        )
+        return "<p>%s</p>" % gettext(
+            "A service fee of {} will be added to the order total."
+        ).format(" {} ".format(gettext("plus")).join(fees))
 
 
 @receiver(order_meta_from_request, dispatch_uid="servicefees_order_meta")
@@ -217,11 +275,11 @@ def order_meta_signal(sender: Event, request: HttpRequest, **kwargs):
     else:
         try:
             reseller, user = get_reseller_and_user(request)
-            meta['servicefees_reseller_id'] = reseller.pk
+            meta["servicefees_reseller_id"] = reseller.pk
         except ResellerException:
             pass
     return meta
 
 
-settings_hierarkey.add_default('service_fee_skip_addons', 'True', bool)
-settings_hierarkey.add_default('service_fee_skip_free', 'True', bool)
+settings_hierarkey.add_default("service_fee_skip_addons", "True", bool)
+settings_hierarkey.add_default("service_fee_skip_free", "True", bool)
diff --git a/pretix_servicefees/urls.py b/pretix_servicefees/urls.py
index fae3b55..4a98794 100644
--- a/pretix_servicefees/urls.py
+++ b/pretix_servicefees/urls.py
@@ -3,6 +3,9 @@ from django.urls import path
 from .views import SettingsView
 
 urlpatterns = [
-    path('control/event/<str:organizer>/<str:event>/settings/servicefees/',
-        SettingsView.as_view(), name='settings'),
+    path(
+        "control/event/<str:organizer>/<str:event>/settings/servicefees/",
+        SettingsView.as_view(),
+        name="settings",
+    ),
 ]
diff --git a/pretix_servicefees/views.py b/pretix_servicefees/views.py
index 41f67fb..ed15957 100644
--- a/pretix_servicefees/views.py
+++ b/pretix_servicefees/views.py
@@ -1,83 +1,98 @@
 from django import forms
 from django.urls import reverse
 from django.utils.translation import gettext_lazy as _
-
 from pretix.base.forms import SettingsForm
 from pretix.base.models import Event
-from pretix.control.views.event import EventSettingsViewMixin, EventSettingsFormView
-from pretix.helpers.money import change_decimal_field
+from pretix.control.views.event import (
+    EventSettingsFormView, EventSettingsViewMixin,
+)
 
 
 class ServiceFeeSettingsForm(SettingsForm):
-    service_fee_abs = forms.DecimalField(
-        label=_('Fixed fee per order'),
-        required=False
-    )
+    service_fee_abs = forms.DecimalField(label=_("Fixed fee per order"), required=False)
     service_fee_percent = forms.DecimalField(
-        label=_('Percentual fee per order'),
-        help_text=_('Percentage of the order total. Note that this percentage will currently only '
-                    'be calculated on the summed price of sold tickets, not on other fees like e.'
-                    'g. shipping fees, if there are any.'),
-        required=False
+        label=_("Percentual fee per order"),
+        help_text=_(
+            "Percentage of the order total. Note that this percentage will currently only "
+            "be calculated on the summed price of sold tickets, not on other fees like e."
+            "g. shipping fees, if there are any."
+        ),
+        required=False,
     )
     service_fee_per_ticket = forms.DecimalField(
-        label=_('Fixed fee per ticket'),
-        help_text=_('This fee will be added for each ticket sold, except for free items and addons.'),
-        required=False
+        label=_("Fixed fee per ticket"),
+        help_text=_(
+            "This fee will be added for each ticket sold, except for free items and addons."
+        ),
+        required=False,
     )
     service_fee_skip_if_gift_card = forms.BooleanField(
-        label=_('Do not charge service fee on tickets paid with gift cards'),
-        help_text=_('If a gift card is used for the payment, the percentual fees will be applied on the value of the '
-                    'tickets minus the value of the gift cards. All fixed fees will be dropped if the tickets can '
-                    'be paid with gift cards entirely. This only works if the gift card is redeemd when the order is '
-                    'submitted, not if it\'s used to pay an unpaid order later.'),
-        required=False
+        label=_("Do not charge service fee on tickets paid with gift cards"),
+        help_text=_(
+            "If a gift card is used for the payment, the percentual fees will be applied on the value of the "
+            "tickets minus the value of the gift cards. All fixed fees will be dropped if the tickets can "
+            "be paid with gift cards entirely. This only works if the gift card is redeemd when the order is "
+            "submitted, not if it's used to pay an unpaid order later."
+        ),
+        required=False,
     )
     service_fee_skip_addons = forms.BooleanField(
-        label=_('Do not charge per-ticket service fee on add-on products'),
-        required=False
+        label=_("Do not charge per-ticket service fee on add-on products"),
+        required=False,
     )
     service_fee_skip_non_admission = forms.BooleanField(
-        label=_('Do not charge per-ticket service fee on non-admission products'),
-        required=False
+        label=_("Do not charge per-ticket service fee on non-admission products"),
+        required=False,
     )
     service_fee_skip_free = forms.BooleanField(
-        label=_('Do not charge per-ticket service fee on free products'),
-        help_text=_('Note that regardless of this setting, a per-ticket fee will not be charged if the entire order is free.'),
-        required=False
+        label=_("Do not charge per-ticket service fee on free products"),
+        help_text=_(
+            "Note that regardless of this setting, a per-ticket fee will not be charged if the entire order is free."
+        ),
+        required=False,
     )
     service_fee_split_taxes = forms.BooleanField(
-        label=_('Split taxes proportionate to the tax rates and net values of the ordered products.'),
-        help_text=_('If not split based on ordered products, the tax rate falls back to the event’s base tax rate or no tax, if none is given.'),
-        required=False
+        label=_(
+            "Split taxes proportionate to the tax rates and net values of the ordered products."
+        ),
+        help_text=_(
+            "If not split based on ordered products, the tax rate falls back to the event’s base tax rate or no tax, if none is given."
+        ),
+        required=False,
     )
 
     service_fee_abs_resellers = forms.DecimalField(
-        label=_('Fixed fee per order'),
-        required=False
+        label=_("Fixed fee per order"), required=False
     )
     service_fee_percent_resellers = forms.DecimalField(
-        label=_('Percentual fee per order'),
-        help_text=_('Percentage of the order total. Note that this percentage will currently only '
-                    'be calculated on the summed price of sold tickets, not on other fees like e.'
-                    'g. shipping fees, if there are any.'),
-        required=False
+        label=_("Percentual fee per order"),
+        help_text=_(
+            "Percentage of the order total. Note that this percentage will currently only "
+            "be calculated on the summed price of sold tickets, not on other fees like e."
+            "g. shipping fees, if there are any."
+        ),
+        required=False,
     )
     service_fee_per_ticket_resellers = forms.DecimalField(
-        label=_('Fixed fee per ticket'),
+        label=_("Fixed fee per ticket"),
         required=False,
-        help_text=_('This fee will be added for each ticket sold, except for free items and addons.')
+        help_text=_(
+            "This fee will be added for each ticket sold, except for free items and addons."
+        ),
     )
 
 
 class SettingsView(EventSettingsViewMixin, EventSettingsFormView):
     model = Event
     form_class = ServiceFeeSettingsForm
-    template_name = 'pretix_servicefees/settings.html'
-    permission = 'can_change_event_settings'
+    template_name = "pretix_servicefees/settings.html"
+    permission = "can_change_event_settings"
 
     def get_success_url(self) -> str:
-        return reverse('plugins:pretix_servicefees:settings', kwargs={
-            'organizer': self.request.event.organizer.slug,
-            'event': self.request.event.slug
-        })
+        return reverse(
+            "plugins:pretix_servicefees:settings",
+            kwargs={
+                "organizer": self.request.event.organizer.slug,
+                "event": self.request.event.slug,
+            },
+        )