diff --git a/library/include/mobilisis/calculator_functions.h b/library/include/mobilisis/calculator_functions.h
index 1354e4a..57d8b02 100644
--- a/library/include/mobilisis/calculator_functions.h
+++ b/library/include/mobilisis/calculator_functions.h
@@ -12,9 +12,37 @@
 #include <QDateTime>
 using namespace std;
 
-class Calculator
-{
+class Calculator {
+    QDateTime m_start;
+    mutable uint16_t m_timeStepCompensation = 0;
 public:
+    explicit Calculator() = default;
+    explicit Calculator(QDateTime const start) : m_start(start) {
+        m_start.setTime(QTime(start.time().hour(), start.time().minute(), 0));
+        qCritical() << "init m_start time:" << m_start.toString(Qt::ISODate);
+    }
+
+    void setStartDateTime(QDateTime const &start) {
+        m_start = start;
+        m_start.setTime(QTime(start.time().hour(), start.time().minute(), 0));
+        qCritical() << "set m_start time:" << m_start.toString(Qt::ISODate);
+    }
+
+    QDateTime const &getStartDateTime() const {
+        return m_start;
+    }
+
+    QDateTime &getStartDateTime() {
+        return m_start;
+    }
+
+    void setTimeStepCompensation(uint16_t timeStepCompensation) {
+        m_timeStepCompensation = timeStepCompensation;
+    }
+
+    uint16_t getTimeStepCompensation() const {
+        return m_timeStepCompensation;
+    }
 
 	/// <summary>
 	/// Gets duration in seconds from cost
@@ -60,6 +88,7 @@ public:
                 cfg->SpecialDaysWorktime.size() == 0);
     }
 
+// testing public:
 private:
     // Introduced for PaymentMethod::Steps (e.g. Schoenau)
     // For tariff of following structure: only steps, no special days, nonstop.