SAFC VAFC same stuff... VAFC just has a basic vtec on / off feature....
Most .. well ALL vtec controls only turn vtec ON / OFF at a certain RPM, Honda designed VTEC to be turned on with oil pressure is correct, manifold pressure is correct... engine load is correct and rpm is correct.... it shouldn’t be turned on / off !! not only you need to provide the correct ignition and fuel for the cross over period, no vtec controller does this, and not many after market ecu’s do this either !!

Regards James