I was thinking of it more along these lines: -- his nadir's have all been pretty late (+6.5 and +7) in the past few days so any insulin from this am should be long gone by then. This is the situation where I feel most uncomfortable about what to do - when the pmps is relatively (or is this case absolutely) low
"should be" is the key. Yes, it should be, but in this case, the numbers (to me) tell a different story. They look like they have been going down since AMPS, so his "nadir" in this case was late. It may have happened between +7 and +12, but you can't know for sure. The only other cycles I see like this one on his spreadsheet was the AM cycle on 10/6, and AM on 10/11.
Carryover and/or overlap don't happen often, perhaps, but they do happen. Cycles can and do last longer than 12 hours with PZI/Prozinc.
ETA - and while some might think that a cycle that lasts longer than 12 hours indicates that a dose is too high, I don't agree with that. I think sometimes a cycle just lasts longer than 12 hours. And rather than avoiding them, it is better to take advantage of them when they do happen.
If you see a cycle where PMPS is lower than AMPS, but you see definite lower numbers
in between, you can safely assume nadir has come and gone, and the numbers are rising, the insulin is wearing off or has worn off, and it's a rising number you are shooting at. But when you see a sliding number from AMPS to PMPS, you can't assume even that "nadir" has happened yet.
All that said, I would have supported a small dose tonight, .5u was as high as I was willing to suggest. And it might have been a long night, but I would have been happy to stay up and help if you needed help. I'm off work tomorrow, so I wasn't worried about a curfew
I would have first asked if Murphy is a kitty who will pretty much eat on demand, because it is likely you would have had to feed him "off schedule". If so, I think you could have shot, and planned on monitoring for at least 5-6 hours after shooting.
I learned when I used to "hang-out" in the TR forum that a person never advises a shot on a cycle where the caregiver is likely to have to lose sleep unless that person is willing to stay up all night with the caregiver. And I did so quite a few times. So while I might give what is seen as "aggressive" advice at times, I don't do so lightly.