Taking your kitty off insulin was a big mistake. In this forum, we do not drop the dose from 1u to none. Our dose adjustments are generally done in 0.25u increments for non high dose cats.
When the insulin was stopped, he got a double whammy: a bounce and no insulin to help him clear it.
Simba is very bouncy and you are missing half your data by not getting any nighttime tests at all. He could do so much better but you have to get some decent data so you know how low he’s going. The way to get to a good dose is knowing when to raise or lower the dose based on the nadir.
Under SLGS, he earned at 0.25u reduction when he dropped below 90. In reality, his dose should have been dropped to 0.75u on the evening of 12/12 and then again to 0.5u on the morning of 12/14.
I suggest you start him back at 0.5u and be sure you get preshot tests both cycles, at least 2-3 tests in the daytime cycle, and at least two tests in the evening cycle (e.g. +2 and before bed). After a week on the dose, do your weekly curve.
You can then make dose adjustments, if necessary, based on the weekly curve and SLGS.
Also, he doesn’t need an insulin change. You should give Lantus at least six months before you determine if he needs an insulin change.
What will help you put the puzzle together is some additional testing and trying to be as consistent as you can on dosing and shot times. While Lantus does allow for some flexibility, it’s most helpful to be consistent as you are trying to get him to a good dose and you gather some data.