i believe this works to a point. if you are going to train your lagging body part twice a week you need to make sure your eat enough to be able to repair them faster than everything else since you will be breaking them down twice in a week. i do agree with hitting them twice tho if you have a lagging part. I also noticed if i get a cheat meal a week ill have that cheat meal post workout of the lagging body part. Usually the cheat meal is higher macros than most meals so it helps recovery.
EAT BIG TO GET BIG