IME its a negotiated corporate thing for any savings.

When I was forced to use Concur it would connect me to SWABIZ to finish and get me 5% off BS fares.

Big whoop dollar wise but the BS could be justified as a few dollars cheaper than AT, get lots of extra points and sweet business class seating on AirTran metal, for about 2 years during their long integration period. Too bad that ended.