Just casually, I wore the chase downs for about a month and I didn't feel the zoom once. Really disappointing to me as the units were supposed to be huge but I felt more bounce in the 12 & 13.
Ultimately it's too hard to say for every particular person. But I'm getting the feeling that for PERFORMANCE, a lot of guys want that 1:1 fit and the XV has a bit of toe room (length)...so they're trying half size down. At TTS with the knit construction, it opens the possibility that they'll stretch out, resulting in a sloppy fit both side to side and front to back. So with an average/narrow foot, going down half a size may be snug at first but after a break-in may result in an optimal fit for ball.
But from a purely CASUAL standpoint, these are perfectly TTS IMO. Not too tight and ample wiggle room for the toes.