Rocky has earned a dose reduction of 0.25U. Please reduce the dose to NO MORE than 0.75U.
Best insulins for cats are Prozinc, Lantus, Levemir.
Please don't let your vet prescribe Vetsulin (aka Caninsulin), made for dogs and most cats do not do well on it.
We have ways to save you money on the Lantus. Get the script from your vet and send it to Marks Marine Pharmacy. Info is here in this link:
Ordering Lantus, Basaglar, or Levemir from Canadian pharmacies
If you get a prescription for Prozinc, order it from Chewy.com, but your vet has to approve the script AFTER you have put your order in with Chewy and many vet clinics are horrible at following up with Chewy. Bug your vets office every day, to make sure they have done the prescription authorization.
The Novolin insulin simply does not have the duration needed by a cat. Duration is 6-8 hours usually, and that is why you are seeing the nadir so early in the cycle, +3 to +4.