Docs can mix up the botox or Dysport to whatever concentration they feel is best for the patient and the areas being treated. As long as you are getting good results, then be happy and trust your doc. 1 area is usually $300-350, 2 areas is $500-600 and 3 areas is $675-800. (glabella or frown creases are 1 area, lateral canthi or smile lines on the sides of the eyes together are 1 area, and forehead creases are 1 area).
The number of units per cc I a mathematical measure of concentration. I depends on the dilution that your doctor uses. The Botox comes feeze dried and your doctor must add saline. Adding 5 cc of saline makes the concentration 2 units per 0.1 cc. Different doctors use different dilutions and it depends in what they are most comfortable with. It is the number of units injected that matters, not the concentration.