That still isn't bad at all. Only 70 point rise with no insulin. I definitely think the pancreas is helping out. In cats I have seen in this process, the pancreas helps for a little while and then stops (so a little insulin is needed) or it helps out on a limited basis (like the last cycle) but still needs a boost of insulin to help.
The trick is careful monitoring during this stage. If you give a shot and the pancreas kicks in too, he can go lower than you were planning. So your +4 test is good. And it isn't overnight - sometimes pancreas plus tiny doses takes several weeks. Our goal for remission (a diet controlled diabetic) is 2 weeks between 40-120 OFF insulin.