Their researching a $100 fare difference? That's nuts. Someone in your A/P department needs to find something better to do or you need to find a new job. It will cost them more than $100 to research the fare difference, and that's only if the travel agent notes at the time of ticketing that there was a difference. Ours push the lowest fare (but exclude WN since those flights do not show in their system) but I have never seen them note when you do not pick the lowest fare. We also do not have to book a connection, so they only note (when they do) a lower fare difference if you a) opt for a higher priced nonstop over a cheaper nonstop and that difference is more than $100-$150 or b) opt for a connection when the nonstop is cheaper, again by more than $100-$150.