I considered deleting the post, but this seems more cowardly than just admitting I was wrong. But TIL something!
I think it would be easier to go to thebank now and then to exchange some of your $100 for lower value bills than to do the opposite.
Besides, if there are places that don't take bills less than $20, there are a lot of places that aren't going to let you pay with only $1 bills. I can't imagine a car dealership letting you do that. Or if you want to buy a home, etc.