diff --git a/library/src/calculate_price.cpp b/library/src/calculate_price.cpp
index 30b8c9a..da93550 100644
--- a/library/src/calculate_price.cpp
+++ b/library/src/calculate_price.cpp
@@ -352,7 +352,8 @@ CalcState CALCULATE_LIBRARY_API compute_price_for_parking_ticket(
         QDateTime &start_parking_time,
         int netto_parking_time,
         QDateTime &end_parking_time,
-        struct price_t *price)
+        struct price_t *price,
+        bool prepaid)
 {
     CalcState calcState;
     double minMin = tariff->getPaymentOptions().pop_min_time;
@@ -391,7 +392,7 @@ CalcState CALCULATE_LIBRARY_API compute_price_for_parking_ticket(
                         start_parking_time,         // starting time
                         end_parking_time,           // return value: end time
                         netto_parking_time,         // minutes, netto
-                        false, true);
+                        false, prepaid);
         double minCost = tariff->getPaymentOptions().pop_min_price;
         if (cost < minCost) {
             calcState.setDesc(QString("minCost=%1, cost=%2").arg(minCost, cost));