First a comment on the spreadsheet. How are you getting the conversions from the US to the World tab? I used to enter on the World tab numbers and let it do the automatic conversion to the US tab. The decimal places on the World tab are just a bit off putting. I am in Canada and can went to the World tab first. Not a big deal, just curious.
I think it's time to try 2.25 units again. He didn't technically earn a reduction back to 2.0 units last time you were there by going under 50. And technically, he's considered a long term diabetic now - diabetic more than 1 year. With TR that means reductions earned by going under 40, or a week in all normal numbers. For cats that don't hold reductions well, some people use the guideline of 3 times between 40 and 49 before reducing.
With TR, we don't usually hold doses more than 10 cycles, unless they are pretty well regulated. Frodo has to get rid of those red, pink and higher yellows. More insulin can do that.
As for the 8th and 9th, the night of the 7th he hit at least a 52, maybe lower. I would have gotten a later test to make sure he wasn't still dropping.