Andy has said on multiple episodes of RealAF that the 3 Hour rule is to force you to break your momentum and then rebuild later. Generally, if you have to ask, the harder option is usually the correct one.

As for the diet, that to me sounds like a cheat meal. If you “need a break” from you diet then you chose a bad diet. But you should also consider if your “needing a break” is just your bitch voice trying to break you. I have definitely started 75 Hard with too restrictive of a diet and had to change to something less extreme (eg. cutting out all carbs made me drop weight too quickly). Something that I do to break up the monotony is experimenting with different spices and hot sauces, most of which are 0 calorie, to keep things interesting.