Yes, it’s kind of an idiot’s guide to managing diabetes – if he’s between 7&10 give him 1 unit, if he’s between 10&12 give him 2 etc.
I had an unfortunate time as a teenager when I was in hospital about to have my tonsils out and some idiot misread the sliding scale during the night, leading to me being given insulin to deal with my “high” blood sugar of 3. I was too low to argue effectively against it. Unsurprisingly I was unconscious pretty soon after the injection and was sent home because I wasn’t fit to operate on. That’s why I always want the husband with me now, to fend off the idiots when I’m not capable of doing so.