Here is yesterday's post for continuity, we like to link the previous post here, so people can see some history.
https://www.felinediabetes.com/FDMB/threads/help.246437/
Short answer, no

. You just started Lantus, and had a little oopsy on what you thought was 1u but it was actually 3u. He's likely bouncing at the moment, from hitting some lower numbers that he isn't used to. Lantus is a depot insulin, so when first starting out, it takes 5-7 days for the depot to build and to see what the dose can do. Time for a little patience. Hold the 1u, then evaluate after a week. As I mentioned yesterday, we make dose adjustments in 0.25u, but we also need to see how low the dose is taking Shooter, which is why mid cycle tests are important. You need to gather some data to see how the insulin is working, before making any dose adjustments.
Perhaps it is time to have a look at the dosing methods we follow here,
dosing methods. If you are still feeding dry food at the moment, you will need to follow SLGS.
and please do set up your spreadsheet, since suggestions or advice given going forward will depend on the test data you get. No one can (or should) really properly advise you on dose without seeing test data first.