I'm curious why you're not on the Lantus forum? There are People there with many years of experience that can help you get your cats Blood glucose down.You need advice from "Experienced People" They can advise you about the correct dose to give Tiger.
I posted here because it's not a question about his insulin or dosing. Honestly, I just assumed this would be the best place to find general info, that other folks might have input on, who may not frequent the lantus forum.
On his SS you switch dose frequently. That's not how your supposed to dose Lantus.
Those High #'s aren't good. My Cat Ravan goes into High Bounces & his BG goes to black sometimes. He was recently diagnosed with Kidney disease. I think the High bg damaged his kidneys.
Your goal is to try to get his bg to blue & green.
Believe it or not, I do want to keep Tiger steady on his insulin dose. The random (I think two) 1.5u doses are because I was nervous about his lowish number - coming from vetsulin and not seeing those good numbers made me scared for a hypo, when I wasn't going to be around to monitor him. I was attempting a .25u decrease from 2u, when he had a <90 reading, but my vet suggested I go back to 2u since we were still getting those 600+ more often than not.
I feed Ravan when ever he's hungry as much as he wants. He's 16 yrs old & also a big Kitty,not over weight. He started to lose weight but now he's stable. (He's 12 lbs )He eats mostly a Raw diet all his life. If you read the Information on the insulin Lantus you'll understand better what's happening & why he's Hungry.
I feed the cats twice a day, to coincide with Tiger's insulin and my work schedule. Neither cat eats their entire meal right away, they will have some, then come back later. I do not take away the food during the day/night, but also I'm at work or sleeping so I can't give more smaller meals. I give one can every meal for sure (Two cans a day, per cat). Sometimes I do one can each kitty, and split a third between them. Sometimes this extra is cleaned, sometimes it's left.
There are some people that took their cat off dry food & the Kitty went into remission. The dry food your giving Tiger is probably why his BG is so HIGH. Once his BG comes down he won't be so Hungry or lose weight.
I have NOT given Tiger dry food in almost three months. Not since his diagnosis, with the exception of a fairly serious drop when I was trying to get his number back up. I was seeking advice about starting to give him SOME with his wet food every meal time, for some more calorie dense food. I gave him a single tablespoon of Young Again Zero Mature today with dinner.
Please go on the Lantus Forum & ask for Advice. They will help you to Help your Tiger.
Best of Luck to you & Tiger
Genuinely, thank you for the luck. We are still pretty new to this, especially considering all of the experience here and are doing the best we can

SO much better than when he was initially diagnosed, but we still have a long way to go.