Whats IFS? Well Sasuke didnt beat Kinshiki and he wasnt even trying to where Kinshiki was on attack mode the whole time. He could easily power up his weapon with amaterasu and break Kinshiki axe's. Im not sure which chapter but when Naruto used kyuubi mode for the first time infront on Kawaki,Kawaki mentioned that Naruto is maybe stronger then Jigen and why else would Jigen take power from Juubi other that he knows that he will fight Naruto or SasukeWe aren’t talking about “IFS”. Fact is Sasuke didn’t defeat Kinshiki.
True Jigen did Absorb ten tails chakra, but that doesn’t mean Sasuke was stronger with using ten tails chakra. You can’t assume.