Ordering new books; midlist or not?

A ton of midlist books offered this week. 

Basically, I order any book that the wholesaler has inventoried above a certain number. It's a pretty high number. Usually I'll order about 4 or 5 of these books per week. That's all the "bestsellers" per week I can handle. Remember, I constantly reorder books that have sold, (the backlist) which so far has seemed a safer bet.

Of course, I order any book I am interested in and think I can sell, no matter how many copies the wholesaler has...

Anyway, below the sure-to-buy number are books that are, well, semi-popular. (When I use these terms, it refers to what the book industry itself considers hot, which is somewhat predictive--but not totally.)

I sometimes pick a couple of these as well.

This week, there was an extraordinary number of these midlist books. So either it's the time of year to release those, or my wholesaler is bulking up inventory for the summer. 

Each year I order new books, I'm learning something new. 

In another 20 years, I should have this figured out. About the time I'm 90 years old.