Interesting info....
If you use ATA with the SWA Cr. Card, you probably do not get double credits on the card -- so I guess the double credits for the WN fares for 7 RT would about offset the slight reduction needed in trips (converted from ATA to RR).
I dont know the ATA routes or frequency or prices.... but these may come into play. Also does ATA have the no fee for changes and use the funds later if you cancel. Impt. items.