I don’t see a post for today so I’ll just put my thoughts here. I’m very glad to see you reduced the dose because a 43 on an AT and a “LO” on the FS warrants a reduction for safety.
I know you said you thought he was low yesterday morning because he hadn’t eaten like normal and he vomited during the night but that doesn’t tell the whole story. We can surmise that not eating as much and vomiting can cause the BG to drop (because it does to a certain degree) but cats often go low at night and, with no tests, it’s putting him at great risk. We certainly don’t expect you to be up all night but a +2 and a before bed test would really be helpful in knowing how low he might be going. If he does need a dose increase at some point down the line, you’ll need to know how low the dose is at the current time before you increase safely.
I also understand that you’ve been doing this for 2.5 years. Last year, a member whose kitty was dx in 2010 and was a nice, flat green for quite some time, got a little complacent with testing and came home to find he had had a severe hypo. He didn’t make it.

While I’m not trying to use scare tactics, I just want you to understand that things change constantly with our diabetic cats. A dose that has looked fine for many, many cycles might suddenly be too little or too much. I encourage you to try and get a few tests in at night in addition to the PMPS. Also, with his history of DKA, I wouldn’t be skipping shots. A 133 on an AT is a safe number to shoot with a full dose. Granted the 43 is not a number any of us would have shot but stalling and letting the BG rise would have allowed you to get some insulin in him.