It looks great! In my experience, your cook is similar to what I’ve had happened with smaller cuts of brisket and pork butt. The time to cook to temp is longer than what it would be for for larger cuts - that is the hours per lbs. it’s crazy, I know but now you have the experience with the smaller cuts. And it could be due to the thickness of the cut - it ay only be a 4lb flat, but the thickness of that 4lb flat is probably the same as an 8lb flat, just not the same length or width.
The pork butt time actually looks about right to me. I think all the pork butts I’ve smoked at 225 are around 2 hours/lb.
But, for future cooks, if you are using butcher paper, get the bark set where you want it, then wrap. Sounds like this is what you did, but just to keep that in mind.
Also, if you are going long on a cook and coming up on eating time - don’t forget about the oven with a high temp to bring to temp. If your bark is set, the meat is above 140*, theory is no more smoke is taken on (just what I’ve read, not sure if it’s true or not) but you could get your last few hours in the oven and then be able to rest with hotter temps and wrapped in foil.
Make sure you have a beverage during the lazy q process as well...if you like to partake in beverages

that helps with not worrying and letting it ride!
Keep on smokin!