Bill,
According to G Vrecheck in this link:
http://www.pjdenterprises.com/baseba...pps_print.html
the 3rd series was printed such that the 1st 40 cards (#131-170) were double printed while the remaining 20 cards (#171-190) were single printed. This seems to follow with the commonly accepted mid-series scarcity for gray backs.
Did you notice the same quantity in glossies i.e did they follow this same pattern?
Z