Bouncing is one of the most frustrating parts of the sugardance. There's no simple answer to it other than in most cats, it eventually stops.
Bounces are caused by 1. the BG dropping too low, 2. dropping too quickly, 3. dropping into numbers the body isn't used to being at anymore (or any combination of all 3).
The liver releases stored sugars and hormones to bring the BG up quickly. In the first 2 cases, to "save" the cat from possibly crashing.
With the 3rd reason, the same thing is going on (the liver is kicking in) but it's because of a "perceived" low, not an actual one. Most of our cats are actually diabetic for quite some time before they become sick enough for us to get them diagnosed so their body has had time to get used to living in those higher numbers. So even though dropping from 350 to 200 isn't anywhere near "too low", the body still says "wait a minute! I'm not supposed to be this low anymore!! Better release the hormones and sugars!!!"
With time, the body re-learns that it's OK to be in normal numbers and the bouncing slows down and hopefully stops.....but we've also seen cats who bounced all the way to OTJ.