He is definitely bouncing all over. I think the dose is too high overall. For example, the pmps on 4/24 was 363 and he got 3 units. The next morning, after 12 hours, he was 126 . Not only is that a low pre shot number, but he may have dropped very low overnight. So if 3 units gave him that kind of response on a pink, you wouldn't want to give 3 units on a much lower number. (Today may just be a completely weird cycle with the lows which his body probably reacted to with a spike in glucose so I would just monitor and make sure he doesn't decide to dive mid cycle. It could also be a high flat cycle - no telling) The other complicating factor is a lower card food which may be tilting the numbers downward.
If he were mine, I would lower the dose. Maybe on a pink pre shot, 2.5 for a few cycles to allow things to shake out. If you get a pre shot under 200, do just as you did - wait until you are sure it is rising, not falling. But then shoot less, not the same. Maybe 1.5 or 2 for a yellow? Hold these doses for a few days and see if things flatten out and he quits bouncing up to the black numbers.
There is a protocol for ProZinc that we put together in my signature. It may be helpful.