It does store the settings with power/no power, etc. I've had the same boost controller.
The control unit only has 2x wires for power, GND and IGN - there's no constant power.
You could easily figure out how to set it yourself, the lower the GAIN the "lazier" it comes onto boost, the higher the GAIN the "harder" it comes onto boost but will have the tendency to spike.
SET just determines how much boost you want to run, please note SET the scaling does not equate to any boost figure.