So we've got a Moen setup in our bathroom, and the shower adjustment range is just tiny. It's more of an annoyance than anything, but I was wondering if it was "fixable"
In a nutshell, I'll describe it as if it was the hour hand on a clock...
If you have the temperature knob set at say 11:00, everything is fine. If you even NUDGE the knob to 10:59, it gets a lot hotter, and vice-versa if you bump it over to 11:01, it's a drastic swing to cooler.
I've found that doing temperature adjustments literally has me tapping the end of the handle to move the knob half a degree or so.
Just a guess but I think the anti-scald adjustment lever may be loose. This is located under the handle (and may also require removing the cover plate). You could also go to Moens website (Moen.com) and go to the customer service section for specifics on your unit.
If you have never made a mistake, you haven't done much.