I'll tell you this much. I used to do a DBO every two weeks when my hair was relaxed...and it didn't do my hair ANY good.
1. The stylists have been using the blow dryer all day. At least in my Dominican Hair Salon, there had no heat setting on their blow dryer. It's either on or off. So the heat was so excruciatingly hot, you can imagine what kind of damage it must've done on my relaxed hair. You DONT want that heat on your hair -- use a GOOD heat protectant.
2. Again, this was in MY Dominican Hair Salon. Some of the stylists don't understand English. So if you must, speak to someone who can understand English and ask them to repeat in Spanish what you want done to your hair to the stylist.
3. You're paying your money so don't be afraid to speak up and ask what YOU want. I suggest you bring your own heat protectant and deep conditioner, they might skimp a little on you since its their product.
4. I don't suggest you get a DBO...although the results are AMAZING and beautiful. I mean seriously, you get a DBO, your hair is LAID! But the downside? The risks of getting heat damage is pretty high. Maybe invest in a good blow dryer & flat iron (with steam) and straighten it yourself? Because no one will treat your hair as well as you do =]