Rochelle
Let me see if I can provide some info to help but not overload you.
I think you already know that the day is divided into two 12-hour cycles. One begins with the AM preshot or AMPS and the other with the PM preshot or PMPS. If you skip a shot, for purposes of posting a thread here, then the AMPS becomes AMBG and PMPS becomes PMBG even though the SS still says AMPS and PMPS.
Below is a chart to give you an idea of what an active Lantus cycle looks like,
eventually. Jelly's SS probably won't look like this for quite some time consistently, but this is the goal.
Three terms that are
very important in each cycle and that you should eventually be able to recognize on Jelly's SS:
Onset: the time in the cycle when the insulin actually onsets. For Lantus, this can be +2 or +3, generally, but every cat is different (ECID).
Nadir: the time in the cycle where you see the peak action of the insulin and numbers will reach their lowest. This definitely differs by cat but, in a "perfect"

Lantus cycle, would be about +6.
Duration: How long the insulin lasts. Lantus is a long duration insulin with a typical duration of 12 hours but some cats get longer than that and some get less. Absorption from shot to shot can vary up to 50% so you can see how that might affect duration.
Today, Jelly was clearing a bounce and, often, when this happens, numbers just keep coming down so the lowest point is often at the next preshot...or even after. You should always be prepared for an active cycle when Jelly is clearing a bounce.
One thing that can help is feeding the curve. Not all cats need the caregiver (CG) to feed the curve but I believe if a kitt, like Jelly, clears his bounces like he did today, it might help you.
While detailed feeding the curve instructions are a subject to be dealt with separately, it might help him if you fed a portion of food at AMPS,+1, +2, and +3.
It often helps to feed the majority at AMPS and +1 and the rest at +2 and +3. However, this varies by cat and might need to be adjusted. The goal is just to offset the action of the insulin with low carb food so the numbers don't drastically drop early in the cycle.
Darcy suggested you get a +11 test because that will give you an idea of where he is headed by preshot. You will still need to get a preshot test though because numbers can change quickly in some situations.
It's also good to get a +2 test every cycle that you can because it will give you an idea if it's going to be a busy cycle. If the +2 test is similar or less than the preshot, you should count on it being a busy cycle.
I think that's enough to load you with for one day.