ALOT of people post this about susano requirements.............. http://www.narutobase.net/manga/Naruto/392/2
BUT itachi said, ""along with tsukuyomi and amaterasu, that awoke within these eyes on that fateful day""
CLEARLY HE'S TALKING ABOUT HIMSELF ON THAT "FATEFUL DAY", HE'S NOT SAYING THE ONLY WAY TO UNLOCK SUSANO IS TO HAVE TSUKUYOMI AND AMATERASU
NOW Sasuke states THIS http://www.mangahere.com/manga/naruto/v50/c464/16.html
THE ONLY THING YOU NEED TO UNLOCK SUSANO IS TO HAVE DOUBLE MANGEKYOU SHARINGAN, NOT AMATERASU AND TSUKUYOMI SPECIFICALLY.