Hello and welcome to this forum. Make sure you read the yellow starred sticky notes on the top of this forum, including the one on dosing methods. People here pick one of two methods, which ever suits their lifestyle and goals for their cat. Based on the dosing method, we can help you better on dosing.
You seem to be missing a number of the PMPS tests. And early on were changing the doses a little faster than we would for the numbers you were seeing and now are holding quite long. Looks like you started out with just one dose a day? Can you tell me a bit about the decision making behind the earlier dose changes?
Lantus is a depot insulin, so you need to hold the dose at least six cycles for the depot to build and see what a dose can do. We also would be making changes by 0.25 units at once, no more, for the numbers you have been seeing.