I don't know if you ask for a recount over 12 statewide delegates, unless some of these CDs are close as well. There are a few right now, but Cruz would also put CD4 at risk by asking for a recount.
Nate Silver made a point about the "inevitability of a contested convention." He says he doesn't see it. For example, it looks like Trump will win MO by less than 2000 votes, and yet he'll probably walk off with around 42 of 52 delegates. I think my numbers are right, but it's a big margin in comparison to the vote total. Same in IL, where Trump should take well over half.