I've seen this happen with other cats. You have to go up in dose until you hit that sweet spot that finally helps get control of their blood sugar. Then the cat stays in normal numbers and the pancreas begins to heal and put out a bit of insulin as well.
Then the injected dose is too big! The way a cat comes down the dosing scale is very individual. Some work their way down a quarter unit at a time. Some go down in leaps and bounds - even with skipped shots to reduce the depot. Looks like Shiloh may be the second kind. Just keep an eye out at any point if it looks like the numbers are trending up, it may signify the reductions were too large or too close together. For now, as long as she stays green like this, I'd keep the 1.0u until she goes below 50.
I read through the rest of last night's post - I wouldn't assume that a cat couldn't go into low numbers after a skipped shot. Not at all. There is the whole depot to remember - the 2.5u you shot yesterday morning will continue to influence and help control her blood sugar for as many as 6 cycles after that shot. So if you see low numbers like you did last night, I would assume you need to continue monitoring until she is stable and you are confident she won't go back under 50.
I would not just leave food and go to bed on a 51 after the previous test was in the 40's. That's just me, but i don't think that sounds safe. Cats can wobble back down after the food carbs wear off. If you absolutely HAD to leave her, I'd leave a large amount of high carb food out, but the ideal situation would be to keep monitoring until she hadn't had food for at least a couple of hours and she was still over 55 or so, even after you were sure the carbs would've worn off.