I would definitely raise the dose more aggressively with trace ketones in the picture. The slowest I would consider going as long as ketones are around is an increase of 0.5u every 2 days (4 cycles per dose), and frankly I would probably raise it faster if I were doing it myself, though I'm not sure what guidelines to give you on that front.
I have no ketone experience, but I'd hate to see things turn into a crisis. If they are at a level where you should be headed to the vet (I don't know at what point that is recommended? maybe post on Health if you don't already know?), please do so. Sometimes in giving advice I forget that at times the best approach is not to finess the dose with trial & error & testing like we do here, and just get to a vet. Just mentioning that to be on the safe side
since I just don't know all that much about ketones. I know it is important that they are eating well and getting fluids, which I think you noted in your spreadsheet, so that's good.
I'm surprised actually that you got a few good #s here and there on doses that look alarmingly high to me. To me that suggests that either Meatball is on a higher carb food/dry food (?), or there may be something else going on where he might actually need a higher dose. Sorry I don't recall any background if you have posted on Health, so I don't want to comment too far, but I'm thinking it's at least possible that he does need quite a bit more insulin. I don't know much about kitties on higher doses though, so perhaps occasional good #s like that are typical? I just don't know, sorry.
As for testing, as others have said if you can get some mid-cycle checks in (in the +5.5 - +7.5 -ish range ideally, to check for a nadir), that will help you raise the dose more confidently. If he is going from 400 down to 100 and back to 400, it's a very different picture than 400 to 350 and back up to 400. With my cat on PZI I found that I generally trusted the results on cycle 3 of a new dose. With many cats, I have been told you can tell by the 2nd cycle, but others can take a little longer til it's clear. Until you see nadirs even remotely in good #s (like under 200), I wouldn't worry too much at this point about letting a dose settle. You've waited long enough to be sure that any rebound from the previous high doses has had time to clear, so IMO you are now free to pick up the pace, and send those ketones packing!
Hopefully additional eyes will be along soon. If you want to post daily, that is ideal to be sure that all of us are keeping up with the latest #s and can give you the best advice. I would also consider adding "ketones" in your post header as long as you are seeing them, so we don't lose sight of that angle (and hopefully that will draw in some with more ketone knowledge/experience as well).
Welcome, and great job getting the data you have thus far!
