Damage from foaming and cavitation isn't necessarily immediate. It is a little here and a little there. It also would be worst in fast stops and hills. You might get away with it in Kansas, but not San Francisco.
Since 4x4's usually have deeper oil pans and 1 qt extra, you could certainly add more unless you off-road.
Only way to know for sure is to put a window in your oil pan, run the engine with extra oil and tilt it, in all four directions.