No it isn't, C stated that Sasuke was more skilled with Amaterasu, he has greater control over it and can manipulate the flames better than Itachi. The only thing Itachi is better at is Tsukuyomi.
No he said" Don't tell me Sasuke is more efficinet"
He DID NOT say sasukes was stronger or had better control, Efficent he meant by using it in a smart way. You saw how good Itachi was Chasing sasuke with Amaterasu...... That was control wasent it. Plus C NEVER seen itachi use Amaterasu or even seen itachi in his WHOLE LIFE.... So how can he even judge. But anyway he said "DOnt tell me he's more efficinent" Thats not saying sasuke WAS better
Itachi is better at sasuke at Taijutsu (Watch the fight again)
Especially,
ESPECIALLY better than him a Regular Genjutsu and Definantly Tsukiyomi. And Susano'o, especially since he has the ultimate defense Yata Mirror AND Blade of Totsuku which zetsu said makes him invinvicble inside.
Like i said before, Itachi's Amatarasu destroyed JIRAYAS Toad mouth trap in a second. (Which Jiraiya said NO ONE EVER destroyed or escaped that, not even pain.