Click on the link provided by Coyoteman in post #14...maybe that article will help.
"My calibration shows that the changes (mutations) were occurring two to four times faster than previously thought,"...people have overestimated the time. It wasn't so long ago." (and) previous DNA data flawed..."I hope the impact of my paper will be to bring the molecular timing more in line with the archaeological record," he says. "This is what you want your work to do."
Means that the author is bending one factor, statistical norms for mutation, in order to accomodate another, accepted interpretations of a time line.
What accounts for the 'two to four times greater' rate of mutation?