Thanks, Pseron. I'll implement a check on the last one to make sure that won't cause issues, and look into the former. Might be as simple as pulling the latest SkyProc, but I'll check over the code a bit too. I can't imagine why carts would collide, though..
First thing on the list after I get back from work. It has been a headache, I can say that. Too many issues arising just to make increased spawns bug-free... >.< There's so much stuff that's rigged up to the barest point of working in vanilla Skyrim, that anything touching into the system tends to break it fairly easily.

I'll make one in a bit/something.