Some reading for you: Glucose toxicity:
What is it & what should I do about it?
Basically their bodies get used to higher numbers, so you need to get to a higher dose to break through it. It's a type of insulin resistance. Can I ask why you gave 3.5 unit last night? That restarts the cycle count on this dose. Also, there was no mid cycle test the night before than. With the numbers he's in, ideally you'll not spend more than 6 cycles on a dose before increasing, if he keeps showing you nothing below 200. But you can only increase safely that often with TR as long as you are getting at least two tests per cycle.
Here is the link to your last post here, which we include for continuity:
https://felinediabetes.com/FDMB/thr...-be-getting-higher-with-dose-increase.257255/