I just got mine done yesterday. Everyone is directed to one common window,
where you are assigned a token number. It does not have anything to do with
the purpose of your visit. You then have to wait for the number to be called and after that it only takes about 20 minutes for your passport to be stamped. I had a very pleasant expeience, inspite of the fact that just as my number was about to be called, the fire alarm went off and we had to be evacuated. We were back in the building after 45 minutes and everything resumed like normal.