Can the Minimum Passing Score be curved up (above 70%)? meaning, average, passing

richer1983

It was my understanding that the Minimum Passing Score was determined by taking the average of either the top ten scores or the top one percent and then multiply that by .7 (to obtain a number that is 70% of the top scores). I have heard many say that the top one percent are averaged but I also met a grader who told me that it was the top ten scores in years past.
So, by that rationale the minimum passing score can never be more than 70%, meaning you get a 70% you are guarenteed to pass. Is this correct? If not, can someone explain to me how the MPS can be curved up?

Thank you!