Fix in Calculator::GetPriceForTimeStep():

Allow some tolerance (of 3 minutes) when looking up the
	current time-step value in the duration-array.
	Otherwise, when corossing a minute-boundary, it can happen to
	not find the match and returning a price of 0 (which is almost
	always wrong).

library/src/calculator_functions.cpp

@@ -3584,7 +3584,9 @@ uint32_t Calculator::GetPriceForTimeStep(Configuration *cfg, int timeStep, int p
             qCritical() << "(" << __func__ << ":" << __LINE__ << ") timeStep" << timeStep;
         }
 
-        if (timeStep == pun_duration) {
+        // allow some tolerance when searching for [timeStep == pun_duration]:
+        // this might happen when crossing minute boundaries
+        if (std::abs(timeStep - pun_duration) < 4) {
             qCritical() << "(" << __func__ << ":" << __LINE__ << ") return price" << price;
             return price;
         }