Bronk: If no spits USED the 4x20mm in combat, why would you add it? Yes they removed them for performance reasons, but also because they felt "2 were good enough". The 190s took the other route, piling more guns and more ammo onto the frame as much as it could carry. Sometimes they put bombs on it so large the tail wheel couldn't touch the ground.
Totally different philosophy between the two nations here. Not bias. Just how it was.