Sandy,
Have we given you the link to the PZI document?
http://www.felinediabetes.com/FDMB/viewtopic.php?f=24&t=32799 It's too much for one sitting, but has a lot of good information. PZI generally has a smile curve - am preshot, then a slow decline to around +6 which is probably the lowest number and then a rise to a number near the am preshot. The hope is that both the preshot numbers and the nadir start to get lower over time. A regulated cat is in the 200s at preshot and in the low 100s or double digits at nadir, but not under 40. (We say a cat in remission ranges from 40 -120 without insulin and is in the double digits the majority of the time.)
If the +6 (nadir) is in the 40-50 range, that is lower than we want to see. It calls for intervention, with low carb food first. If the number continues to fall, then higher carb. Finally syrup for a number that continues to go down.
So Max's curve was a perfect shape, but a little steeper than what might feel good for him. Dropping from the 400s to the 100s could make him feel crummy. But it is encouraging, as Carl said, because the insulin is working. It is possible that he has been dropping lower mid cycle at night and that makes the preshots higher. (We call it a bounce. His body reacts to a lower number than usual by releasing glucose which raises his blood glucose levels.) Or the new diet may be slowing kicking in. Only time and data will tell.
You can try to soften that curve with food - feeding smaller amounts more often. Ditto on the DM. It's mainly liver and cats get tired of the taste. The good thing is that you can return it. Purina accepts all returns on their foods. Just say he won't eat it.......Fancy Feast has ingredients that are just as good and there is more variety that cats like better.
You and Max are looking good. BTW, I have meant to tell you from the first day. Love your sign in - and yes, there is definitely hope!