I think the differing shots am/pm may have been before Peg got to FDMB or at least to this board.
When switching from Lantus to Lev, we suggest people reduce the dose to 70% of the Lantus dose. Then shortly after that Peg began "fast-tracking" Toby, increasing every 4 cycles when she could, sometimes holding a little bit longer, until she got to a dose that was getting him into better blood sugar control. When Toby was controlled by a dose, she held the dose. When he lost regulation at a dose, she increased.
When a cat gets to about 6u per shot we usually start thinking about getting the cat tested for a high dose condition. Oren's not to 6u yet, but he's likely got something going on. Toby hasn't been tested so we don't know if he has acro or iaa, but obviously he has something causing a need for a high dose.
Yes, Lantus & Lev are dosed the same, it's just when the switch is made typically we reduce it and increase if needed. Some cats don't need as high of a dose on Lev.