Reductions are given as a safety measure; they are not randomly picked numbers. People who follow TR have a lower reduction number than SLGS because as a general rule, they are able to test more often and have more data on how their cat responds to insulin. While at the moment you can test more frequently (which is awesome, because more testing = more data on the SS, and more knowledge/safety) you still really don't have any data on how she will respond to a consistent dose. What you *do* have is data that shows that, as
@Wendy&Neko said, *without* a depot and with several missed shots, 0.5 U brought her too low on the SLGS protocol. She has earned a reduction because 0.5U is too high a dose for her now, knowing what we now.
(Looking back at her Dec 13 pm cycle she got 1 U, then two consistent 0.5 U doses on the 14th, and earned a reduction by preshot in the am on the 15th when she was at 4.6. Most likely she dropped even lower during the night of the 14th, since she seems to nadir around +6ish, so that 4.6 was after she'd been climbing a while.)
If you shoot 0.5U twice daily now, she'll most likely earn another reduction in a day or so (go below 5) but more concerning she may go too low (under 2.7). Mallie's already shown she can drop hard and fast lol. Of course, she's your cat, it's your call

Just be prepared to watch closely the next few days and nights as her depot builds.
Likely, a consistent 0.25U will give her safer shooting numbers twice daily, allowing twice daily dosing with no skipped shots (so her depot can stabilize).
Regarding feeding: Many (most?) cats on Lantus do better with more smaller meals fed through the day. It's a matter of trying to get the carbs into her while the insulin is working, but (again as a general rule, but not always) not after nadir. So instead of giving her a big meal at preshot, it would be a good idea to try to give Mallie maybe 1/2 can at preshot, then maybe 1/4 can at/around onset (+2 or +3) and another 1/4 can around +5 or +6 when she's about to hit/hitting nadir. This will help to keep her "surfing" the greens instead of dropping into deeper numbers, and then having a harder time to get her numbers up in time for preshot.
(Feeding twice a day is meant for other types of insulin such as caninsulin, which cause a fast and early dramatic drop in blood sugar but have no lasting effect, rather than the long-acting insulins like Lantus).
Also, if you keep notes on when/how much you feed (I'm talking her regular LC food) you'll get a better idea how she responds to carbs (some spike on LC, some need HC just to budge) so you'll have a better idea how/what to feed when you *need* to bring her up. More data is always great.
With love, Nikki