? 6/20 MOUSE AMPS 302, +4 180, +8 65, Why Big drops?

This is nothing new for Mouse, and still befuddles me. She'll start high, then wham! big drop in numbers! I recently upped her dose about 1/8, so, I don't see the insulin dosage being the cause. Food was given, nothing out of the ordinary.
It makes it very hard to monitor, to predict. I had to go out today, and thought the 302 down to 180 was something, but when I returned, 65?