2 things -
you can't totally safely do 80% anymore on starts, it seems, although i think its usually fine. i don't think the game was intended to be so picky that a guy could quit after just a few missed starts, or perhaps even 1. but it does appear to be the case. i would stay at/north of 80% for the entire season myself, i am not comfortable going less, as the examples seem to have included early missed starts leading to early complaints. when the first guy posted about his dude leaving with 1 or 2 missed starts, i didn't really buy it, but there's several examples that have been posted by this point. (this topic is definitely not settled science and if anyone has examples of dudes leaving with minimal promise violation it would be awesome to see them!)
the second thing is, my understanding is the post season can't hurt you, but it can help you, when it comes to promises. it definitely used to be that way, now, not so sure. but anyway, if you are in the doghouse, i wouldn't consider the fight over when the CT rolls around. if you are safe heading into the CT, you are good to ignore promises the rest of the way.