For all 3 of mine, if they are really "ready" for the level they are competing, they make very little progress during the comp season itself - sure a touch here, a bit there - scores go up a bit overall...but the only times we have seen big changes during the season is when DD was first competing (and went from scratching bars to competing them) and the 4 months total that she trained and competed old L6 (coach was willing to do this fast to get to L7 before the changes...), where she really was still learning everything initially...
For the boys, they have been through a gym change, 3 coach changes including a doozy of a mess going on right now, and that is probably impacting...DS older really is sick of his level and works the next level in most practices, not much more he can do where he's at...and DS the younger's scores vary by up to 5 points based upon his concentration factor by the last 2 events....
Honestly, I HATE comp season....money, long drives, frustrated kids (or happy but the same performance can lead to either depending upon who else is there...), etc....I actually enjoy watching a bit more (other than the panic they might kill themselves part) when they are "new" and still trying to just complete routines....easier for them to feel good about achievements....
Our comp season is only Jan to March for all three and they are traveling at least overnight for all meets - tired, its winter so there is at least one virus that comes through, etc....I don't expect tons of changes until they are consistently uptraining again...