Degreeing a Cam Shaft

Hey, not to get in the middle of the mud slinging but I have a question.
When do you read the peak on a ramp?
By that I mean, right when it reaches the peak, when it's at the peak or right when the indicator starts back down. On my experience there seems to be a few degrees when the lifter hits the side, top and back side of the lobe.
What do you guys measure, or how do you call the number?
As long as the cam lobe has a symmetrical grind, max lift should be at the centerline of the lobe.