The likelihood of finding someone at PayPal that knows that PowerStore was built using eCart is pretty slim. If you won't believe PayPal's list of approved carts, why would you believe a random support person at PayPal?
All things in the world cannot be boiled down to a yes or no question. Obviously it is not as simple as your are trying to force me to acknowledge.
I've exhausted all ways to explain this and we aren't getting anywhere. I suggest that you wait until the WA staff returns after the weekend and you can take it up with them. I'm just a volunteer.