Kakashi Inconsistency

[The Demon Hawk]

MS is another level of Sharingan, that's why. The levels can be increased or decreased, but the dojutsu itself can't be turned off.

He got the eye at 3T so that's the lowest he can take it. He's not turning his eye off, he's lowering it from MS to 3T. He can't lower it further because that's the state he got it in. Same reason Nagato can't lower his Rinnegan to EMS or 3T.

That's not quite true. Even if he received the eye at MS, he'd still be able to take it to 3T.