Ok, the PMPS was high, the BG went sky high after that low green mid-day, but how was Nico feeling and acting?
Did Nico get any food or treats when he dropped down to that low green?
Brainstorming a bit here, of things you could try.
1. Eliminate the Dr. Elsey's Clean Protein. I know it's supposed to be low in carbs, but maybe Nico is reacting negatively to it. The carb calculator I use says it's 7-8% carbs.
2. Double check to make sure there is no "contraband" food that Nico might be getting to. From another pet, from someone else in the house sneaking him food, from anything left out on the counters of the kitchen or elsewhere, no food dropped on the floor, etc.
3. Maker notes on which flavor of the FF you are feeding. Make notes on the SS of the + times when Nico gets fed. Trying to find patterns there.
The only other idea I had is to try one of the depot type insulins, Lantus or Levemir. The gradual release of the insulin from the "depot" storage area under the skin could help to even out the BG levels.
Please don't bash your head against the wall Em, because we wouldn't want to see you with a concussion.