http://www.cnn.com/2011/11/04/travel...-bumping-tips/
"If your ticket does not show a fare (for example, a frequent-flier award ticket or a ticket issued by a consolidator), your denied boarding compensation is based on the lowest cash, check or credit card payment charged for a ticket in the same class of service (e.g., coach, first class) on that flight."
We had assigned seats as well.