The answer is yes and no. All that matters is what AFR comes out the tail pipe. You can do that in several ways. You can manipulate the MAF scaling,or the openloop table and even injector scalings. Generally you want to rescale the MAF until fueling corrections are -/+ 5%, but it's not 100% " black and white" this has to be done. "Tuning fuel" is tuning ALL the fueling tables,not just the MAF table. Obviously tuning fuel would also incorperate changeing the factory calibration open loop AFR's as well since from they are pig-rich.