Bui Vien OKTs operate from Lobby of this hotel(Ha Vy), corner of Bui Vien and Do Quang Dao, at night time.
Saw a lineup of 12 girls come on scooter, into lobby. Mostly SYT type grade 5-7/10 looks. Price was quoted 1M +300k room fee upstairs. When I walked away he dropped to 1.1 total. I suppose you could easily nego for 1M room incl. Delivery to hotel also possible.