Just want to give you something to think about for the next time you get a lower PS.
Although 185 might have felt low in the face of you having to leave for 4 hours, it's important not to look at the number you get at PS in isolation.
You do such a good job of getting spot checks that we can see that at +8 he was at 136 so it looks like his numbers were on the rise, this is what we would expect at the end of the cycle.
Then consider how the Lantus cycle operates, when you shoot, unlike other fast acting insulins, Lantus takes a while to onset, usually around the two hour mark though it can vary from cat to, some onsetting earlier, other's later.
So with a starting point of 185, the BG will continue to rise until onset (around 2), add to that the effect of his breakfast that he has just eaten, and his BG is quite likely to be significantly higher by the time the insulin onsets. Also it's not unusual for a kitty, who is not used to spending time in green to bounce after a nice cycle, so that 185 may even be the start of a bounce, though that was by no means clear this morning. So this mornings number, to a CG with experience, would not have felt like a risky number to shoot, especially as you are coming round at +4.
Are you able to leave food out for Max? Do you have an autofeeder? Is he a decent eater?
On days like today an autofeeder can really help, I found it eased my nerves if I could leave food in George's autofeeder, I would leave LC or even HC if I was really worried he might be going a bit too low for comfort, and it allowed me to be able to get out of the house.
By contrast to today's numbers and to illustrate when you might want to play closer attention, look at the pm cycle on 1/30, pmps was 402, at a first glance that might seem like a number you can shoot and not worry about, but, if you look back to +9 in the am cycle, we can see he was 522, and more importantly the morning cycle was looking like a bounce cycle from the greens on 1/29. That drop of 122pts, was max signalling his intention to clear a bounce, he was dropping into pmps, shooting when a bounce is clearing, can lead to them gathering quite some momentum, now, that's not a reason not to shoot, but you might want to take some preventive action, on that day I would have grabbed a +1, and you would have probably seen his numbers dropping fast early on, that then gives you the opportunity to feed to stay ahead of the drop and feed the cycle, its easier to slow them down than it is to bring them up once they've dropped too low, or if you were having to head out you might choose to leave higher LC food out to help him surf in good numbers and stay safe.
I learnt the above lesson early on one day when BFG started clearing a bounce, being a newbie, I didn't feed proactively, this resulted in me fighting BG in the 30's and 40's for a good few hours, George ate 9 ounces of 28% carb wet food on that day, thank god he was a good eater, that didn't happen to us again, with the help and guidance of more experienced members I learnt to keep him safe with food. I learnt through trial and error how much food and what carb % I needed to keep him safe.
One last thing, because Lantus is a depot insulin, the first part of the cycle is still being largely controlled by the depot of the larger dose, (the 5u) and so will play out just as it would have normally, but will probably lead to the pmps being a little bit higher than it would have otherwise been.
Hope that makes sense.
Learning to look at the ss and using all the data you have been so good at gathering can really help you help Max better and get him into a good BG range, which will in turn help him start to feel so much better.