diff --git a/msp/importers/builder.py b/msp/importers/builder.py
index 6fd5ea5..8a1aac5 100644
--- a/msp/importers/builder.py
+++ b/msp/importers/builder.py
@@ -165,15 +165,16 @@ class DocumentBuilder:
 		if is_return and qty > 0:
 			qty = -qty
 
-		# ERPNext berechnet amount = qty * rate. `rate` muss daher der
-		# tatsächliche Netto-Einzelpreis nach Rabatt sein (EINZELPREIS aus ADN).
-		# Fallback-Reihenfolge: unit_price → amount/qty → list_price
-		if row.unit_price is not None:
+		# WICHTIG: Kundenabrechnungen nutzen den LISTPREIS, nicht den Einkaufspreis.
+		# Der Lieferanten-Rabatt (z. B. 17,5 % bei ADN) ist unsere Marge und
+		# darf nicht an den Endkunden durchgereicht werden.
+		# Fallback-Reihenfolge: list_price → unit_price → amount/qty
+		if row.list_price is not None:
+			rate = row.list_price
+		elif row.unit_price is not None:
 			rate = row.unit_price
 		elif row.amount is not None and qty:
 			rate = row.amount / qty
-		elif row.list_price is not None:
-			rate = row.list_price
 		else:
 			rate = 0
 
@@ -183,11 +184,6 @@ class DocumentBuilder:
 			"rate": rate,
 			"description": self._format_description(row),
 		}
-		# Listenpreis + Rabatt zur Nachvollziehbarkeit in der UI mitführen
-		if row.list_price is not None:
-			item_row["price_list_rate"] = row.list_price
-		if row.discount_pct:
-			item_row["discount_percentage"] = row.discount_pct
 
 		item = doc.append("items", item_row)
 
diff --git a/msp/importers/subscriptions.py b/msp/importers/subscriptions.py
index 20f9708..1784c4b 100644
--- a/msp/importers/subscriptions.py
+++ b/msp/importers/subscriptions.py
@@ -61,15 +61,28 @@ def upsert_supply_subscription(row: CanonicalRow, *, customer: str,
 def create_event(row: CanonicalRow, *, supply_subscription: str,
                  target_doctype: str, target_name: str, target_row: str | None = None,
                  supplier_import_line_row: str | None = None) -> str:
-	"""Erzeugt ein Supply Subscription Event für eine abgerechnete Periode."""
+	"""Erzeugt ein Supply Subscription Event für eine abgerechnete Periode.
+
+	``rate`` und ``amount`` spiegeln den **Kundenpreis** (Listenpreis × Menge),
+	``cost_rate`` und ``cost_amount`` den Einkaufspreis bei Lieferant.
+	Differenz = itsdaves Marge.
+	"""
+	qty = int(row.qty) if row.qty else 0
+	list_price = row.list_price
+	customer_rate = list_price if list_price is not None else (row.unit_price or 0)
+	customer_amount = qty * customer_rate
+
 	event = frappe.get_doc({
 		"doctype": "Supply Subscription Event",
 		"supply_subscription": supply_subscription,
 		"period_start": row.period_start,
 		"period_end": row.period_end,
-		"qty": int(row.qty) if row.qty else 0,
-		"rate": row.unit_price or row.list_price or 0,
-		"amount": row.amount or 0,
+		"qty": qty,
+		"rate": customer_rate,
+		"amount": customer_amount,
+		"cost_rate": row.unit_price,
+		"cost_amount": row.amount,
+		"reseller_discount_pct": row.discount_pct,
 		"booking_type": row.booking_type or "Billing",
 		"sales_invoice": target_name if target_doctype == "Sales Invoice" else None,
 		"sales_invoice_item_row": target_row if target_doctype == "Sales Invoice" else None,
diff --git a/msp/msp/doctype/supply_subscription_event/supply_subscription_event.json b/msp/msp/doctype/supply_subscription_event/supply_subscription_event.json
index 43442d4..f62461f 100644
--- a/msp/msp/doctype/supply_subscription_event/supply_subscription_event.json
+++ b/msp/msp/doctype/supply_subscription_event/supply_subscription_event.json
@@ -20,6 +20,12 @@
   "qty",
   "rate",
   "amount",
+  "cost_section",
+  "cost_rate",
+  "cost_amount",
+  "column_break_cost",
+  "reseller_discount_pct",
+  "margin_amount",
   "link_section",
   "sales_invoice",
   "sales_invoice_item_row",
@@ -116,6 +122,42 @@
    "in_list_view": 1,
    "label": "Amount"
   },
+  {
+   "fieldname": "cost_section",
+   "fieldtype": "Section Break",
+   "label": "Einkauf & Marge",
+   "collapsible": 1,
+   "description": "Interne Daten (was itsdave an den Lieferanten bezahlt hat) — dient nicht der Kundenabrechnung."
+  },
+  {
+   "fieldname": "cost_rate",
+   "fieldtype": "Currency",
+   "label": "Cost Rate",
+   "description": "Einzelpreis nach Wiederverkäufer-Rabatt (z. B. ADN EINZELPREIS)"
+  },
+  {
+   "fieldname": "cost_amount",
+   "fieldtype": "Currency",
+   "label": "Cost Amount",
+   "description": "qty × cost_rate (z. B. ADN POSITIONSPREIS)"
+  },
+  {
+   "fieldname": "column_break_cost",
+   "fieldtype": "Column Break"
+  },
+  {
+   "fieldname": "reseller_discount_pct",
+   "fieldtype": "Float",
+   "label": "Reseller Discount (%)",
+   "description": "Wiederverkäufer-Rabatt gegenüber Listenpreis"
+  },
+  {
+   "fieldname": "margin_amount",
+   "fieldtype": "Currency",
+   "label": "Margin",
+   "read_only": 1,
+   "description": "amount − cost_amount"
+  },
   {
    "fieldname": "link_section",
    "fieldtype": "Section Break",
diff --git a/msp/msp/doctype/supply_subscription_event/supply_subscription_event.py b/msp/msp/doctype/supply_subscription_event/supply_subscription_event.py
index ba6f50d..77048a2 100644
--- a/msp/msp/doctype/supply_subscription_event/supply_subscription_event.py
+++ b/msp/msp/doctype/supply_subscription_event/supply_subscription_event.py
@@ -3,6 +3,11 @@ from frappe.model.document import Document
 
 
 class SupplySubscriptionEvent(Document):
+	def before_save(self):
+		# Marge berechnen, sofern beide Seiten bekannt sind
+		if self.amount is not None and self.cost_amount is not None:
+			self.margin_amount = float(self.amount) - float(self.cost_amount)
+
 	def on_update(self):
 		self._refresh_subscription_denormals()