diff --git a/library/src/calculate_price.cpp b/library/src/calculate_price.cpp
index 01275e1..f38bb21 100644
--- a/library/src/calculate_price.cpp
+++ b/library/src/calculate_price.cpp
@@ -1240,6 +1240,12 @@ CalcState CALCULATE_LIBRARY_API compute_duration_for_parking_ticket(
                 }
 
                 if (carryOverStart.isValid() && carryOverEnd.isValid() && carryOverDuration != -1) {
+
+                    // note: in such a case (direct coins) carry-over has been handled
+                    // already in GetDurationFromCost()
+                    netto_parking_time -= carryOverDuration;
+                    qCritical() << __func__ << ":" << __LINE__ << "netto-parking-time" << netto_parking_time;
+
                     // qCritical() << __func__ << __LINE__ << "ticketEndTime.time():" << ticketEndTime.time().toString(Qt::ISODate);
                     if (ticketEndTime.time() > carryOverStart) {
                         // qCritical() << __func__ << __LINE__ << "ticketEndTime.time():" << ticketEndTime.time().toString(Qt::ISODate);