Instead of looking at this as a theory for the hoax, let's add all the facts up about the contradiction you posted. The contradiction would be a fact so maybe build on that to see where it goes. I am of the opinion that too many times people right off facts with a statement of belief. I think we should pile up the facts to make a solid case for each piece of evidence.
Facts Posted:
1. TMZ posted Demerol then Propofol (who else did this)
2. Demerol is regulated (scheduled). Propofol is not, but cannot be obtained without prescription (probably not with one either because who writes a script for this stuff?)