diff --git a/Elwig/Helpers/Billing/EditBillingData.cs b/Elwig/Helpers/Billing/EditBillingData.cs
index 996266b..ac6bce9 100644
--- a/Elwig/Helpers/Billing/EditBillingData.cs
+++ b/Elwig/Helpers/Billing/EditBillingData.cs
@@ -42,7 +42,7 @@ namespace Elwig.Helpers.Billing {
                 dict2[idx].Add("default");
             }
 
-            var virtOffset = dict1.Count;
+            var virtOffset = dict1.Max(e => e.Key) + 1;
             Dictionary<int, Curve> curves = GetCurves();
             decimal[] virtCurves = [.. dict2.Keys.Order()];
             for (int i = 0; i < virtCurves.Length; i++) {