diff --git a/library/src/calculator_functions.cpp b/library/src/calculator_functions.cpp
index e1a247d..fc3bda6 100644
--- a/library/src/calculator_functions.cpp
+++ b/library/src/calculator_functions.cpp
@@ -319,12 +319,12 @@ Ticket Calculator::private_GetCostFromDuration(Configuration const* cfg,
 
     static const PaymentMethod paymentMethodId = Utilities::getPaymentMethodId(cfg);
     static const bool carryOverNotSet = isCarryOverNotSet(cfg, paymentMethodId);
-    static const int minParkingTimeMinutes = getMinimalParkingTime(cfg, paymentMethodId);
-    static const int maxParkingTimeMinutes = getMaximalParkingTime(cfg, paymentMethodId);
+    static const int minParkingTimeMinutes = Utilities::getMinimalParkingTime(cfg, paymentMethodId);
+    static const int maxParkingTimeMinutes = Utilities::getMaximalParkingTime(cfg, paymentMethodId);
     static const bool checkMinMaxMinutes = (minParkingTimeMinutes < maxParkingTimeMinutes);
     static const int durationMinutesNetto = durationMinutes;
-    static const uint32_t weekDaysPrice = computeWeekDaysPrice(cfg, paymentMethodId);
-    static const double weekDaysDurationUnit = computeWeekDaysDurationUnit(cfg, paymentMethodId);
+    static const uint32_t weekDaysPrice = Utilities::computeWeekDaysPrice(cfg, paymentMethodId);
+    static const double weekDaysDurationUnit = Utilities::computeWeekDaysDurationUnit(cfg, paymentMethodId);
     static const double specialDaysDurationUnit = 60.0;
 
     if (!checkMinMaxMinutes) {