I've fed during slough once by accident, darwin hides out for a week or so preshed and I missed the blueeye stage, tossed in a rat and next day had a very cranky python, with a stuck slough over the bulge, I had to carefully assist with small scissors.
Didnt harm him any but stressed him out definately.
I try to avoid it, meals dont come on schedual in the wild anyway, so if its preslough, i skip the meal, till next time, or feed a few days after.
I dont regulate feeds at all, might be two weeks, might be three or four, then 2 weeks again.
Works for me.