I was prescribed 7.5 mg Endocets that contain 7.5mg of Oxycodone Hydrochloride. When I read on the side of the bottle, there was a note that said that 7.5mg of Oxycodone Hydrochloride was equivalent to 6.722mg of oxycodone. Further research showed that all percocetes were this way. Why is it that it says 7.5mg Oxycodone on the front of the bottle but this amount is not actually found in the pill?