The answer to the original question is no. In general the "você" imperative is the same as the present subjunctive. The present indicative for "ele/ela/você" is used as the affirmative command form for "tu". In this case, though, perhaps the reflexive "sente-se" would be more appropriate (I'm not a native speaker so that's just a guess).
Would it be possible to get a round-up of the Portuguese for sit (which is irregular in English)? Please include tu as well as você. Obrigado! :)
I sit = ?
You sit here = ?
Please sit = ?
Please be seated = ?
Sit! = ?
Sit down! = ?
Sit up! = ?
Sit at attention = ?
I need you to sit properly = ?
We have been seated at the bar = ?
We are sitting at the bar = ?
Let's sit at a table = ?
The chair sits outside = ?
I would like to seat myself = ?
Please, seat yourself = ?
Can/will they sit on the ground? = ?
This is where your seats are = ?
This is where they will sit = ?
I have been sitting all day = ?
He sits at his desk = ?
She does not want to sit any longer = ?
Imperative, subjective, interrogative, affirmative, reflexive, intransitive, transitive, continuous, gerund, participle, gerúndio, infinitive... my head is spinning. I mostly know these (separately) except perhaps subjective which seems a bit slippery to me... and the transit ones.
The past forms can wait till I get a handle on the present ones. =}