Bob asked me to chime in last night, and I missed it; my apologies!
Some cats do, for some reason, seem to have more active cycles with better numbers at night. My Mikey did right from the start. If you look at his SS, he'd drop into the 100's and lower at night and have flat cycles in the 200's during the day. For him, it was a matter of waiting out those daytime flats, because a dose increase was not advisable as his PM nadirs were low (and are still lower, in general). IMO, he was experiencing what I called "bouncelets," or small bounces, in the morning from the better numbers at night. And then one day, his liver finally got the message that these new numbers were good, and his daytime numbers have improved, first the mid-cycle readings, and then the preshots. It was a waiting game, and he still has better numbers at night.
If I were you, I'd run a few curves to try and pinpoint your nadir time, and then run some spot checks both day and night at and around that time, as that will help you see if this is a series of bounces or not, and then go from there on dose. I would hold the current dose for six cycles, so that if it IS a bounce, it has time to clear, and then run a curve. From there, you can post your numbers and the dosing experts can give you some eyes. Most cats on Lantus don't need more than 2 units unless there's an underlying condition, but ECID, and some do need more. Finding the right dose and then waiting it out are frustrating, for sure.