Yeah I've run into this issue too. FAST grounds their fuel pump and fan signal while Holley sends out 12v to turn things on.

On the dyno we have to flip flop the wiring on the fuel pump relay depending if we're running a FAST system or a Holley system.

I do think the FAST method is smart, but a lot of pre-built relay kits ground the relay to the busbar so the FAST method doesn't work with them.