I am sorry to hear Buddy is going through a rough spot.
Once you can get your spreadsheet to save with at least your last week worth of numbers, we might be able to help you determine if it is safe to do so. Kitties off their food can get at least half a dose. Cats undergoing anesthesia, who cannot eat, generally get a half dose. I found with Neko, when she wasn't feeling well, her numbers were even higher and it was safe to give insulin. I could always syringe feed higher carb if needed, but seldom did.