diff --git a/library/src/calculate_price.cpp b/library/src/calculate_price.cpp
index 60484f9..f86d641 100644
--- a/library/src/calculate_price.cpp
+++ b/library/src/calculate_price.cpp
@@ -36,7 +36,10 @@ int CALCULATE_LIBRARY_API get_minimal_parkingtime(Configuration const *cfg,
                                                   int paymentOptionIndex) {
     int minTime = 0;
 
-    paymentOptionIndex = cfg->getPaymentOptionIndex(permitType);
+    paymentOptionIndex = getPaymentOptionIndex(*cfg);
+    if (paymentOptionIndex == -1) {
+        paymentOptionIndex = cfg->getPaymentOptionIndex(permitType);
+    }
 
     qCritical() << __func__ << __LINE__ << "paymentOptionIndex" << paymentOptionIndex;
     qCritical() << __func__ << __LINE__ << "permit" << PermitType(permitType).toString();
@@ -69,7 +72,10 @@ int CALCULATE_LIBRARY_API get_maximal_parkingtime(Configuration const *cfg,
                                                   PERMIT_TYPE permitType,
                                                   int paymentOptionIndex) {
 
-    paymentOptionIndex = cfg->getPaymentOptionIndex(permitType);
+    paymentOptionIndex = getPaymentOptionIndex(*cfg);
+    if (paymentOptionIndex == -1) {
+        paymentOptionIndex = cfg->getPaymentOptionIndex(permitType);
+    }
     int maxTime = 0;
 
     switch(permitType) {
@@ -94,7 +100,10 @@ int CALCULATE_LIBRARY_API get_minimal_parkingprice(Configuration *cfg,
                                                    int paymentOptionIndex,
                                                    QDateTime const &start) {
     int minPrice = -1;
-    paymentOptionIndex = cfg->getPaymentOptionIndex(permitType);
+
+    if ((paymentOptionIndex = getPaymentOptionIndex(*cfg)) == -1) {
+        paymentOptionIndex = cfg->getPaymentOptionIndex(permitType);
+    }
 
     int payment_method_id = cfg->getPaymentOptions(paymentOptionIndex).pop_payment_method_id;
 
@@ -321,7 +330,9 @@ int CALCULATE_LIBRARY_API get_maximal_parkingprice(Configuration *cfg,
     int maxPrice = -1;
     static const PaymentMethod paymentMethodId = Utilities::getPaymentMethodId(cfg);
 
-    paymentOptionIndex = cfg->getPaymentOptionIndex(permitType);
+    if ((paymentOptionIndex = getPaymentOptionIndex(*cfg)) == -1) {
+        paymentOptionIndex = cfg->getPaymentOptionIndex(permitType);
+    }
 
     switch(permitType) {
     case PERMIT_TYPE::SHORT_TERM_PARKING: { // e.g. szeged (customer_281)
@@ -474,7 +485,11 @@ int CALCULATE_LIBRARY_API compute_next_timestep(parking_tariff_t *tariff, int cu
     //    return currentTimeMinutes;
     //}
 
-    int const paymentOptionIndex = tariff->getPaymentOptionIndex(permitType);
+    int paymentOptionIndex = getPaymentOptionIndex(*tariff);
+    if (paymentOptionIndex == -1) {
+        paymentOptionIndex = tariff->getPaymentOptionIndex(permitType);
+    }
+
     int const &pop_plus_steps = tariff->getPaymentOptions(paymentOptionIndex).pop_plus_steps;
     int const &pop_minus_steps = tariff->getPaymentOptions(paymentOptionIndex).pop_minus_steps;
 
@@ -654,7 +669,10 @@ CalcState CALCULATE_LIBRARY_API compute_price_for_parking_ticket(
 
     CalcState calcState;
 
-    int const paymentOptionIndex = tariff->getPaymentOptionIndex(permitType.get());
+    int paymentOptionIndex = getPaymentOptionIndex(*tariff);
+    if (paymentOptionIndex == -1) {
+        paymentOptionIndex = tariff->getPaymentOptionIndex(permitType.get());
+    }
 
     double minMin = tariff->PaymentOption.find(tariff->getPaymentOptions(paymentOptionIndex).pop_payment_method_id)->second.pop_min_time;
     double maxMin = tariff->PaymentOption.find(tariff->getPaymentOptions(paymentOptionIndex).pop_payment_method_id)->second.pop_max_time;
@@ -721,7 +739,10 @@ CalcState CALCULATE_LIBRARY_API compute_price_for_parking_ticket(
 
     QDateTime start_parking_time(start_parking_time_);
 
-    int paymentOptionIndex = tariff->getPaymentOptionIndex(permitType);
+    int paymentOptionIndex = getPaymentOptionIndex(*tariff);
+    if (paymentOptionIndex == -1) {
+        paymentOptionIndex = tariff->getPaymentOptionIndex(permitType);
+    }
 
     double minMin = tariff->getPaymentOptions(paymentOptionIndex).pop_min_time;
     double maxMin = tariff->getPaymentOptions(paymentOptionIndex).pop_max_time;
@@ -873,7 +894,11 @@ CalcState CALCULATE_LIBRARY_API compute_duration_for_parking_ticket(
         QString cs = start.toString(Qt::ISODate);
 
         bool prepaid = true;
-        int paymentOptionIndex = tariff->getPaymentOptionIndex(permitType);
+        int paymentOptionIndex = getPaymentOptionIndex(*tariff);
+        if (paymentOptionIndex == -1) {
+            paymentOptionIndex = tariff->getPaymentOptionIndex(permitType);
+        }
+
         int prepaid_option_id = tariff->getPaymentOptions(paymentOptionIndex).pop_prepaid_option_id;
         if (prepaid_option_id == 2) { // see tariff03.json for 502: 2 means no prepaid-option
             prepaid = false;
@@ -913,7 +938,14 @@ CalcState CALCULATE_LIBRARY_API compute_duration_for_parking_ticket(
     CalcState calcState;
 
     bool prepaid = true;
-    int paymentOptionIndex = tariff->getPaymentOptionIndex(permitType);
+
+    int paymentOptionIndex = getPaymentOptionIndex(*tariff);
+    if (paymentOptionIndex == -1) {
+        paymentOptionIndex = tariff->getPaymentOptionIndex(permitType);
+    }
+
+    qCritical() << __func__ << ":" << __LINE__ << " payment option index: " << paymentOptionIndex;
+
     int prepaid_option_id = tariff->getPaymentOptions(paymentOptionIndex).pop_prepaid_option_id;
 
     if (prepaid_option_id == 2) {