How do I change the monster week when transitioning from day 7 to day 1?

By the way, there's an interesting issue with week generation in Heroes of Might and Magic III! There are maps where, no matter what you do, the week will always feature a certain type of monster, and the heroes in the tavern will always be the same. But then there are situations where you load an autosave from day 7, and each week is filled with a variety of monsters and heroes in the tavern... I've tried to understand it, but it's all in vain... :confused: