Bounces go UP, not down
When they bounce, it's because either their blood glucose went too low, it dropped really quickly (like from 400-200 in 2 hours is a FAST drop) or their BG is just lower than their body has gotten used to being. (or a mix of all 3 reasons)
When any of those things happen, their liver thinks there's an emergency and dumps stored sugars and hormones into the bloodstream to bring them back up...but it's not very accurate and lots of times they zoom zoom zoom WAY high....that's a "bounce".
Basically, back when our cats were wild, if their blood glucose dropped too much (like from starvation) their liver would "kick in" and release those stored sugars and hormones to bring them back up so they would have a chance to hunt again and (hopefully) save their lives. Unfortunately, the liver hasn't learned that our civilized kitties aren't usually going to starve to death!
The same kind of thing happens if they drop too much, too fast...the liver doesn't understand that dropping from 400-200 isn't a "dangerous" number..200 is still higher than we'd like, but it "thinks" something is wrong so there go those sugars and hormones again!
Reason #3....our diabetic kitties were probably diabetic for quite some time before we started seeing the signs and found out, so their body got "used to" living in those higher numbers....When the insulin brings it down, even in a "good way", there go Ms Liver again....coming to the rescue when she doesn't need to!
Now as their bodies get more used to being at better numbers, the liver can re-learn what it's like to be there again, and not respond so much, but some cats will bounce all the way to OTJ