Probably the RNAV (RNP) Y RWY 13C approach as -300s were being diverted. Only -700s are set up for RNAV, SWA's -300s can't do RNAV approaches.
the rnav rnp would have set the final at 140kts for the 37...
you could manually fly a 300 on that procedure with that straight in and manage your energy...
you mean to tell me the crew could not manage Vref+5 approach?