What a cat needed for an insulin dose a few weeks ago is no indicator of what they need now. Just because Ravan went to 39 when he was in this dose a while ago, doesn't mean he will again.
As for not increasing because you are seeing blue and green, not true. You look at the nadirs primarily, and a bit at the overall range to see if it's the dose you want to stay at. High green nadirs leave room for an increase. My Neko also had CKD, and I wanted to maximize the amount of time her numbers were below renal threshold. For her, and it took some experimenting, I found that if nadirs were no higher than the seventies, the majority of the overall range was below renal threshold. Having said that, with the 67 a couple night ago, I might hold the dose and see where he is when the bounce clears.