Well here is the update to using a CO discounted ticket standby. On Friday, the 8:42 IAH-SLC flight was 26 people oversold but both my fiancee and I filled the two standby seats and made the flight.

First, I visited the Customer service location and had to pay a $75 fee per ticket for missing our prior flights. Cheaptickets said the fee would be $125 per ticket plus the fare difference.

Second, we were very early and were #3 and 4 on the standby list. (1 and 2 did not show when their names were called.)

Moral of the story, while discounted seats are very restrictive, being nice to the agents at the airport works wonders.