23HM20-0383s with drv8825 drivers (no replies)

I am building a 3d printer with 23HM20-0383s Nema 23 stepper motors, drv8825 drivers and a ramps 1.6 plus. My question has to do with adjusting the Vref of the 8825s. The data sheet for the motors state .38A per phase. Am I correct in assuming that since these motors are bipolar, the current is doubled to .76A per motor total. Therefore, should my driver Vref be set to .2-.3V? I made these assumptions and attempted to turn down my Vref that far and I couldn't get below .38-.4V.
Any suggestions?