Television timeouts in NFL Football

In NFL football telecasts, a 2-minute commerical break follows almost every touchdown. After that break, we see the ensuing kickoff, which is SOMETIMES followed by another 2-minute TV commerical timeout.

How are these “arbitrary” breaks determined? If the network could call a TV timeout after every kickoff return, wouldn’t they do it to maximize commerical revenue? Or is there a formula/quota involved?

LIkewise, we sometimes see commericals during team timeouts, but not always!

(I’m just trying to make my channel-switching technique more efficient!)