Adding fixed offset to current consumption?

I’m looking at using a BLHeli_32 ESC with a current meter and a separate flight controller without a current meter. Is it possible to add a fixed offset to the current meter to account for the current consumption of the flight controller, VTX, GPS, compass, servos, etc.? I can do this on the TX, but it’d be better to do it on the flight controller itself so the current consumption in the OSD is more accurate.