I'm a newbie too, so take what I say with a grain of salt. My Billy is on Prozinc too. The board gives us that "don't shoot below 200" so us newbies have a safety net. Folks who have worked with their cats long enough to have a feel for how they relate to insulin often pick a lower no-shoot number such as 150. It's great that you can get some extra tests on Teal today so you can see how he reacts, but you should be fine with that AMPS of 225.
It can be scary to see those first lower numbers. I've so been there! But it looks like Teal is heading in the right direction. Good for Teal!