OK, I'm back. First suggestion - get some night time tests after PMPS. Maybe some +3 or +4 if that's around bed time? Many cats go lower at night. We determine how to change the dose based on how low it's taking the cat. Hence the importance of those night time spot checks. He could be going lower at night and bouncing. Of course, it could be bouncing from even yellows if he's not used to them, but we don't know that without the data. The night of 7/24 is probably one such lower drop as he bounced the next day.
I'd also mix up those mid cycle day time tests. Although +6 is the average nadir, many cats don't nadir then or vary from cycle to cycle. Maybe that's your only time you can test due to work, but if not, and on the weekends, I'd try mixing up the tests in the +4 to +8 range.
Next, at this size of dose, a 0.25 unit increase is barely noticeable. I'd move to 0.5 unit changes now. And if he's not seeing any greens by 10 units, you'd move to 1.0 unit increases. If there is some sort of condition causing insulin resistance, you can't sit on a dose any longer than necessary. I'd go to 9.0 units tomorrow.
