Ten-Tails can be Ten-Tails only when Gedo Mazo is the vessel for all tailed beasts' chakra. Sasuke used Susanoo as a vessel instead, so it's not Ten-Tails, but, as stated, Susanoo filled with all TB chakra.
P.S. There's a Naruto questions wiki for such questions.
The only issue with that is that by the same logic, Hagoromo wasn't the TT jinchuuriki then. Unless it is the TT when all the chakras are merged and sealed within one's body, but when it's the Sususanoo, it ain't.... it's messy.
Well, the issue of Hagoromo as TTJ and Gedo Mazo has always been problematic due to numerious retcons of Ten-Tails sealing and the creation of the Moon, so there's no safe ground with it.