The time taken to build / upgrade something keeps changing. Why?
This is a result of the power level assigned to either your castle or your workshop changing. This happens when one of three things occur: • A vassal assigned to the castle or workshop is seized or rescued. • A vassal assigned to the castle or workshop changes power level – they have squires/handmaidens drop, have a vassal seized or rescued, etc. • You actually change which vassals are assigned to the castle or workshop. Putting powerful vassals in the buildings you are expanding/upgrading allows a faster production rate.