Libby had a good post about dosing & bouncing here. It's #17 on the thread I just linked.
Depending on what your goals are for Milo, if you're wanting him into green numbers I think it's pretty clear he's not going to get there on 4.25u. The lowest this dose has gotten him is 106 and he's been long enough on it that I wouldn't expect it to get him lower now. One concern that comes with holding a dose too long is that a cat gets accustomed to whatever range their blood sugar is in. Then it takes increasing and even more insulin to bring their blood sugar down. That's called Glucose Toxicity and is the reason for not holding a dose that's not getting the cat where you want them to be.
Just a little more info to add in when you're making decisions.