First of all, whoever suggested that airlines give away bulk seats and don't make any profit is sorely mistaken. You wouldn't last too long with that business model. Airlines sell blocks of seats to consolidators at a agree upon (and usually unpublished fare). The consolidator then turns around and sells those seats at whatever price capitalism supports. If they sell for higher they make money. But they take the risk if the seats sell for les or go unsold.

I went online (ua.com) and looked at the receipt for the flight in question and under Airfare it lists "BULK" and under taxes it lists $166. The invoice from my travel agent lists Base Fare of $1923.65 and taxes of $166.32 for a total of $2089.97.

My guess is that United does not have so much a policy that bulk tickets are ineliible for PQD. Rather, my guess is that they don't know how much was paid for the ticket so they can't easily award PQD. This is my theory.