Ron,
They probably were not all on the same sheet. This sheet of Piedmont 150s has Karger, Schaefer, Mullin and Lindaman on it. The others would have been on other sheets most likely.
https://photos.imageevent.com/patric...203%20Full.jpg
One thing we'll never know is if these players were pulled at different times. Poses could have been pulled one at a time or a few at time, or all at once.
Also, even if they were all pulled at the same time, a normal distribution would likely have one or two poses that are extra tough to find just based on randomness.
There were clearly a ton of changes made to sheets during the entire print run. It wouldn't surprise me at all if these guys were pulled at different times which lead to the disparity in populations now.
Finding this pattern was an awesome discovery. Within the group, there are certainly different tiers of toughness for individual players. Figuring out that part of it may not possible.