Board Thread:Theories and Speculation/@comment-31099706-20170327120301/@comment-734582-20170327152040

BakumatsuWarrior wrote: It definitely seems watered down, since time manipulation didn't seem to be involved. I think this is because Sasuke resisted that effect. Itachi had no problems with Amaterasu and Susanoo, i don't see why his Tsukuyome would be weaker. On the other hand, it's the one jutsu Sasuke already felt the effects of a few times. I think Sasuke was simply becoming resistant to it.

So yea, IMHO it's just used as an argument to make Itachi seem better than he was.