DRV8718S-Q1EVM: Setting IDRV_LOx in GUI for Ultra Low Current Drive Strength

In DRV8718S-Q1EVM GUI, I am setting the IDRV_LO1 bit to 1 for low current drive strength. HB 1 is set to HSS with an external resistor load from HB1 to GND and PVDD is 13V. I would like to evaluate the SW node rise time when the drive strength is set to its lowest (IDRVP_1/IDRVN_1 = 0b for 50uA). 

I am not seeing a difference when IDRV_LO1 is set to 0 or 1. Are there any other registers I would need to set for this to work? Right now with the above settings, the rise time is 320ns. 

Thanks!