According to the rules posted on the OnePass website:
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Mileage Credit for Cancelled Flights
When you are ticketed in advance and your flight is cancelled on the day of departure, you receive full mileage credit for a re-accommodated flight. Exceptions include flights cancelled by uncontrollable circumstances (e.g., work stoppage or weather). If you are re-accommodated on Continental Airlines or a OnePass airline partner, you will receive mileage credit for the new flight(s) only. </font>
Sounds dubious, was the weather any better at IAH then EFD? How many people got the taxi ride?
A letter to OnePass is in order.