I believe you are looking at an old rendition of the information from AAHA.
Here is more recent info (click on the blue bold print). We’ve been using Lantus and Levemir here in this forum since 1996. We actually have a protocol for Lantus and Levemir that was printed in the Journal of Feline Medical Surgery and updated in a subsequent veterinary journal. I don’t mean to disparage your vet but any vet who knows even a little about feline diabetes typically prescribes Lantus or ProZinc, although ProZinc is not as good as it’s predecessor, PZI. I actually do not personally know any vet that prescribes Vetsulin other than the occasional one I see here (although it’s more common in the UK). It is difficult to get the BG under control with Vetsulin and it requires monitoring day and evening cycles.
Sadly, my baby girl passed five years ago. Initially, I fed her different Wellness canned varieties ranging from 3-10% calories from carbs and a 13% canned food to control lower numbers. Then I switched to ZiwiPeak canned food and, the last few months, I also did a homecooked balanced diet. How much you feed depends on Susie’s caloric needs. That varies by cat and takes some investigation. If Susie’s weight has been stable, you can calculate how many calories you’ve been feeding her to keep her weight stable and you will want to continue with that as much as possible. If she has lost or gained weight, I’d weigh her (it’s easy to get a pet scale), feed her a tiny bit more or less, depending on whether she needs to gain or lose weight, for a week and then weigh her again. You do this until her weight is stable where you want it but if you are decreasing her food, you want to be sure you do not decrease by more than 1% a week. Do it slowly.
As to when to feed, that depends on the cat and the insulin. Vetsulin onsets quickly and so you must have food on board before you even give her the shot. You then want to feed her at probably +1 and +2.
This information will give you more detailed answers on feeding a cat who’s on Vetsulin.
I do not want to come off as being critical in any way, but please restore her SS to the full version. We need to see the entire SS. There is a reason why. If you need more room for remarks, please let me know and I’ll fix it for you. It is
absolutely imperative that you test her at night. You don’t have to test her all night or as much as you do in the a.m. but cats frequently go low at night and by shooting and not testing, with the way Vetsulin works, you are really, really risking her having a symptomatic hypoglycemic episode and Vetsulin is not as forgiving as Lantus. It’s a much harsher insulin.
Ok--you asked so I will tell you.
The first thing you are doing wrong is not testing before
every single shot. I cannot tell you how many times I’ve had to help members who have woken up to an AMPS of 30 or even lower. Thankfully, they tested before they shot because if they hadn’t, and they’d given insulin, their cat would have likely died from hypoglycemia. You
must test before every single shot if you want to keep her safe.
The second thing you are doing wrong is not testing at night. If we can’t see what her BG is, we can’t offer you much help and neither can your vet. If she is going low at night, she could be bouncing high in the morning but you’ll never get that under control if you don’t test at night. Again, you don’t have to test all night but you need to see where her BG is headed and feed accordingly.
The third thing is not feeding her often enough. Without some carbs to work with the insulin, the BG drops fast. When it drops fast, it rises fast. I don’t know what the %calories from carbs are in the FF Classics you are feeding but alot of members use them here. It is incorrect that “it won’t change the scores...no matter how many times I test”. The BG drops and you have to feed to be sure it doesn’t drop too low because if it does, she’s going to bounce back high. When cats clear bounces, the BG drops fast and low, again. It’s a constant cycle. The more data you have, the more you understand her cycles (onset, nadir, duration) and that’s important for getting her BG under control.
I know you’ve been given alot of material but that’s what FD is constantly about....reading, learning. I still do it or else I wouldn’t be able to offer solid advice here. We are all constantly reading. If you have a few minutes to look around this site, you will see an amazing amount of information especially in the Feline Health Index and FAQs section. Many of us have worked hard to provide that information to help members with their diabetic cats.
What she is doing is totally normal. You have to remember that insulin is a hormone, not a medication. Thus, it doesn’t react as a medication. Hormones affect our bodies in different ways at different times. The best way to approach FD is to take a deep breath and understand that it is a marathon and not a sprint. It takes time and patience and data while remembering that your kitty is your beloved kitty and not just her BG. Sometimes we do get a little too data focused.
Anytime her BG is higher, she will urinate more. I don’t know why she had issues urinating before and only your vet can help you with that. But anytime the BG goes up and sugar spills into the urine, drinking and peeing will increase.
Quite honestly, Susie’s BG doesn’t look that bad. I can show you hundreds of SSs at the same time of being diabetic as Susie and they look so much worse. So pat yourself on the back for the testing that you have been doing. And note that anytime Susie is really hungry.... her BG is likely low although not always so you can’t you that solely as a means for knowing when to test.
I’ve corrected my sentence with a strikeout. What I meant to say is that feeding later in the cycle, after nadir, can slow down the duration of the insulin and, in some cases, stop it cold. 
