To answer your question about the difference in cycles - because she is a cat.

The vet who posts here sometimes once said that we can make the shot the same, the food the same, the times the same, but we can't control the other things that happened that day. Maybe she slept more or less than usual; maybe she ate a tiny bit more or a tiny bit less. Who knows?
Sorry about the fur shot. Oh well, she is doing well. You will get back on track. I'd suggest your usual 1.25 tomorrow am unless she is sky high.