Once again, we need those mid cycle tests to know what is going on. I suspect he went lower at nadir (low point in cycle) than he has been in a while, and yes, then he bounced. Hold tight and try to get those mid cycle tests, they are very important, espectially if you are raising doseage.
I know I sound like a broken record, but try try try to remember not to panic at high preshot numbers. The nadir is the key. High preshots tell you to be wary of ketones, but in and of themselves they do NOT mean you should raise the dose. If the cat is getting a reasonably lower nadir, we would advise to hold the line, and let that little pancreas and liver calm on that dose before we change anything. This can take weeks, not days. It is a long process, but its so worthwhile.