

That's hysterical. I presume you've looked at spreadsheets of other cats around here. Neko got up to 8.75 units, and that's not high for an acro.
Another good read:
Chronic Somogyi Rebound: Myths and Fact
For the mirtazapine pill, back in the day before Mirataz, I've seen people refer to the dose as a "crumb". Some people preferred cyproheptadine as less side effects.
Has Xander ever had a CardioPet ProBNP test done? It's sort of a cheaper screening tool for the heart. Some murmurs are benign age related. Neko had several echos in her time, the first time it was just a benign murmur. Certain breeds heart issues are more common plus also for acros so double the reason for her to get an echo. I'll always regret an echo I delayed getting in another cat who had a murmur. After his first echo I was supposed to schedule a second echo for 6 months later. I delayed, finally scheduled it several months later. He passed from thromboembolism two days before the follow on echo. It could have been detected and the cat put on meds to prevent it.