Hello and welcome.
A few observations. First, your spreadsheet is missing the US tab. Probably the majority of people here are from the US, and will need to see those numbers before they can offer dosing suggestions. I suspect you got your spreadsheet template from somewhere else? It doesn't look exactly like ours.
Next, as Judy mentioned, you have been holding the doses quite long. With SLGS, you evaluate the dose every week. If nadirs (plural) are between 90 and 149, you hold the dose. You haven't seen anything under 150 for over a week. Also, I don't know why you are skinnying and fattening the dose. That technique is only good for when you are fine tuning a dose that is already pretty good, which is not where Coco is now. I would stick with 0.25 unit changes for now. By not going up the full 0.25 units, Coco is lingering longer in higher numbers, allowing
glucose toxicity to set in. The names sounds worse than it is. Basically her body gets used to higher numbers and you need to increase to get over it.
Looking back, you should have held the 2.75 unit dose for a week, then increased if numbers weren't good enough. A cat needs however much insulin they need. Don't worry about the dose size. Keep following the SLGS guidelines and you will get there. It's not uncommon for a cat to go up then down, then up, then down in dose.