There is a 15-20% variance in meter readings, so 83 is not very different from a 90 or 92 that you shot last night. The good thing is that she has flattened out quite a bit and it looks like a +2 is a good-enough indicator of what her cycle will be like. So you don't need to test every hour.
I don't know if it's only the food change or whether her pancreas has suddenly kick-started (that happens in some cats where they go from pinks and yellows to blues and greens almost overnight!), but she is doing very well and holding all these back-to-back reductions. She is down from 3.5U to 1U in a week! So hopefully the skipped shot will not affect her very much.
Like I keep saying, at some point, she
MAY not hold the reductions and you want to think about following TR then. Let's cross that bridge when we come to it.