Hey man no i mean it your Bis and tris are huge! i mean it.

But i get what you mean after a hard back day your tris forearms can
be pretty trashed dont want to work them to much. good to give your whole
body or even one muscle group a bit of time off i do it a couple times a year might be a week or 2 then i get back and seem to get better results.
Ever try using more reps/sets with less weight? i get great results
and when i cut i can see a huge diffrence in my bodyparts even it its not a massive weight gain quality is what you want first imo. so its good to mix it up like some body parts might grow better with heavy training others with lighter trial and error thats what its all about no matter how much exp you have or how big you are.