Vet called to check in + saw the spreadsheet with latest numbers. They said to hold the current dose for 2 weeks and do another home curve then, but I feel like he hasn't been reaching high enough levels to warrant a dose at night for the past few days. Is there such a thing as shooting every 24 hours instead of 12, or is this going to affect his progress in some way? How do I know when he doesn't need insulin any more?
We can touch on this in a bit (need to get some work done

) I have an idea you could try.
In the meantime, linking (and copy/paste) a document written by
@Deb & Wink and why the need for caution this morning.
Why the +2 Test is Important - more detail information for Prozinc users by Deb & Wink
More than a number range, think of the percentage of the drop at +2, that may tell you if your cat is going to drop much lower. Think of that +2 as being an indicator of what direction the BG levels may be headed.
With Prozinc, if you see a 40%, 50% or greater drop, between the pre-shot and that +2, that's a serious heads up warning.
If you see a 20-25%, 30% drop, not quite so worrisome. But still be cautious.
Your cat drops 2 color ranges between pre-shot and the +2, pull out your hypo kit and plan on staying up to test.
Your cat drops 2 color ranges between pre-shot and the nadir, that is to be expected. But you don't want the drop to be much more than 50% between pre-shot and nadir with Prozinc.
Cats tend to bounce high if the drop is 50% or more from pre-shot to nadir.
So you steer those mid-cycles with food, to slow down the steep drop and stop the bounces from being too high.
The steeper the drop, the higher the bounce.
It's a balancing act.
The +2 is like an "early warning" for most cats!
If the +2 is about the same as the PS, it's usually a pretty normal cycle...dropping down to nadir and then rising back up again. (About the same means taking meter variance, that 15% variance that hand held glucometers are allowed to have into account)
If the +2 is higher than the PS, that usually signals a bounce, and those are the cycles when you can usually take a break from testing.
If the +2 is lower than the PS, that's your "Early warning" that kitty might be going much lower later in the cycle so it's important to plan on getting another test or two (or 6) in.
It doesn’t work every time or with every cat. But it does hold true most of the time, so keep this in mind for next time.
It also kind of depends on what BG pre-shot your cat started out the cycle with. Lower than normal, keep a closer eye on the cycle. Lower than you are used to shooting, a number you may not have given insulin before, keep a closer eye on the cycle. Stalled and number rose some, but you did a reduced shot, maybe another test or 2 to see how much the number is rising.
It makes a big difference if your cat starts the cycle in the pink 300-399 mg/dL range (16.6 - 22.16 mmol/L) then if they are in the blue 150 mg/dL range ( 8.3 mmol/L).
p.s. Food notes in the Remarks column can be very useful. Helps to interpret what is happening in the cycle. Notes are done on AM and PM cycle basis and notations need to be with the + time format.
Please be aware that these are only my thoughts based on my experience. This is not a scientifically based study, nor is it a published journal article. So “buyer beware” as they say. ECID.
This was based originally on Chris & China (GA) post where she noted the information for lantus users on the +2 test and what it can mean for the rest of the cycle. I took that as a working basis, and fleshed things out quite a bit more for Prozinc users.