The WMTs that I monitor, that had the20' promo, have between 20-30 machines on the shelves. My local, has 29 machines(16 Play) on shelf. And they have sold only one since Fathers day.
However, the stores that did not participate in the promo do not have much inventory(very few Plays)
on the shelf.
You probably can't count up to 20. My WMT had 20ft promo and even the first day they didn't have more than 8 to 10 Play machines. I am not sure you can fit 30 Play machines in the designated space for machines.