I currently have a JWT ECU tuned for Z32 MAFS and 50# injectors. My engine(SR) has 550cc injectors. I want to get a baseline tune on my afc to make it to the dyno

I figured the 50# injectors to flow 510cc which is 40cc less or 7% than the 550cc.

Is is safe to set the safc to -7% across the board or did I do the scale wrong?