Bev --
It isn't a matter of the liver healing. The liver is fine. In fact, because there's a bounce you know the liver is working just like it's supposed to. The bouncing begins to diminish as a cat's body becomes acclimated to lower numbers. At this point, Gus is used to spending time in higher ranges. Those highs become the new "normal" so when the insulin brings his numbers down, the liver panics. The more time Gus spends in lower ranges, the more the liver will "learn" that there's no reason to panic. We affectionately refer to this as, "Liver Training School" (LTS).
I'm not sure I'd be getting up to catch the +6 when Gus' numbers are running this high. I'd suggest you sleep and save it up for the nights when Gus is in low numbers and you need to stay up and test!.