diff --git a/library/src/calculator_functions.cpp b/library/src/calculator_functions.cpp
index a5f3c76..8038e0d 100644
--- a/library/src/calculator_functions.cpp
+++ b/library/src/calculator_functions.cpp
@@ -182,9 +182,8 @@ uint32_t Calculator::GetCostFromDuration(Configuration *cfg,
                                          quint64 timeStepInMinutes) const {
     // for instance, a tariff as used in Schoenau, Koenigssee: only steps, no
     // special days, nonstop.
-    if (cfg->YearPeriod.size() == 0
-     && cfg->SpecialDays.size() == 0
-     && cfg->SpecialDaysWorktime.size() == 0) {
+    static const PaymentMethod paymentMethodId = Utilities::getPaymentMethodId(cfg);
+    if (paymentMethodId == PaymentMethod::Steps) {
         QDateTime const end = start.addSecs(timeStepInMinutes*60);
         return GetCostFromDuration(cfg, start, end);
     }
@@ -194,9 +193,8 @@ uint32_t Calculator::GetCostFromDuration(Configuration *cfg,
 uint32_t Calculator::GetCostFromDuration(Configuration * cfg,
                                          QDateTime const &start,
                                          QDateTime const &end) const {
-    if (cfg->YearPeriod.size() == 0
-     && cfg->SpecialDays.size() == 0
-     && cfg->SpecialDaysWorktime.size() == 0) {
+    static const PaymentMethod paymentMethodId = Utilities::getPaymentMethodId(cfg);
+    if (paymentMethodId == PaymentMethod::Steps) {
         int const timeStepInMinutes = start.secsTo(end) / 60;
         return GetPriceForTimeStep(cfg, timeStepInMinutes);
     }