It can be hard to explain one number - maybe a bounce starting? Look at overall trends instead. When I do that it looks to me that his dose needs to go up. The green was a week ago so it's becoming ancient history in the FD scheme of things. Changing the dose too often can also increase the volatility. I know the yellow PSs make you nervous but 291 is very likely high enough to give a full dose. As he spends more cycles in higher numbers he can develop glucose toxicity, hence the need for a dose increase.
Try to vary the time of your middle cycle tests if you can. The +2 is useful if you're worried about a dose but +3, +5, etc. would be good data too. It fleshes out the dose response picture more.
I suggest:
- you go back to 3.5 u for a couple of cycles and give it even if the PS is high yellow so you see how he handles that dose on a lower PS
- if you don't see anything lower than middle blues at 3.5 u increase to 3.75 u for several cycles
- you try to keep calm if you see high dark green (90s) - that's ideal and you will get used to them!

Humulin is going to give you high PSs most of the time even if nadir range is low-ish. That's the nature of the insulin. Another factor in favour of feeding low carb wet food is that it *can* help give you better BG control. Please consider doing that sooner than later. I know your finances are tight but Friskies pates are very economical. I'm not trying to pressure you here. I just know you'll be more successful treating Victor's FD if his diet is changed. I'm sure your bag of prescription dry food was very expensive and you don't want to waste it.
So - time for you to take some deep breaths, steel your nerves and work on being braver with your dose strategy. You know what to do if he drops lower than is comfortable and you have a good data base now to refer to. You have us here too! I know you don't want to do any harm to Victor and you won't because you're careful in your approach. I can tell you that getting more comfortable with all this involves pushing the envelope (carefully!) and getting through the situations that worry you right now. It's like anything else that we fear.
I apologize if I sound bossy. I KNOW you can do this!