diff --git a/library/src/calculator_functions.cpp b/library/src/calculator_functions.cpp
index 80731de..edff2ed 100644
--- a/library/src/calculator_functions.cpp
+++ b/library/src/calculator_functions.cpp
@@ -133,7 +133,13 @@ std::string Calculator::GetDurationFromCost(Configuration* cfg,
     QDateTime inputDate = QDateTime::fromString(startDatetimePassed, Qt::ISODate);
     inputDate.setTime(QTime(inputDate.time().hour(), inputDate.time().minute(), 0));
     static const PaymentMethod paymentMethodId = Utilities::getPaymentMethodId(cfg);
-    int const paymentOptionIndex = cfg->getPaymentOptionIndex(permitType.get());
+
+    int paymentOptionIndex = getPaymentOptionIndex(*cfg);
+    if (paymentOptionIndex == -1) {
+        paymentOptionIndex = cfg->getPaymentOptionIndex(QDateTime::fromString(startDatetimePassed, Qt::ISODate));
+    }
+
+    qCritical() << DBG_HEADER << "   option index:" << paymentOptionIndex;
 
     if (DBG_LEVEL >= DBG_DEBUG) {
         qCritical() << DBG_HEADER << "          start:" << inputDate.toString(Qt::ISODate);
@@ -1420,7 +1426,10 @@ double Calculator::GetCostFromDuration(Configuration* cfg,
     Q_UNUSED(payment_option);
     Q_UNUSED(nextDay);
 
-    int const paymentOptionIndex = cfg->getPaymentOptionIndex(permitType.get());
+    int paymentOptionIndex = getPaymentOptionIndex(*cfg);
+    if (paymentOptionIndex == -1) {
+        paymentOptionIndex = cfg->getPaymentOptionIndex(permitType.get());
+    }
     static const PaymentMethod paymentMethodId = Utilities::getPaymentMethodId(cfg);
     if (paymentMethodId == PaymentMethod::Steps) {
         if (tariffIs24_7(cfg)) {