Koles definitely needs more insulin. We do not hold doses longer than a week if the numbers aren't where you want the to be. Holding on to a dose too long can result in glucose toxicity. Glucose Toxicity sounds a lot worse than it is. When a cat stays in high numbers for too long, it's body gets used to higher numbers and treats them as normal. It then requires much more insulin to break through to lower numbers.
I would increase his dose to 4.25U tomorrow.
Do you think you can stop feeding the Dr. Elsey's and switch to the TR dosing method? It will help you get Koles to a good dose faster. You are testing enough for TR.