I think, and please forgive me if this is already implemented (didn't see it), that there should be a warning before upgrading the level of your store. In my own experience, our store was just hopping (couldn't keep the shelves full) and then we upgraded to a level 2 store and we quickly found that sales dropped off to practically ZERO. We had full stock of all the level 1 items but because we didn't yet have the level 2 stuff on the shelves people really didn't buy anything. We didn't really have any money to stock the level 2 stuff right at the start, so what should have been a celebration of achievement turned out to almost completely destroy our store.