I can only speculate that an new engine that is completely void of oil may require a little more at the initial fill. This does not explain why a dealer may do the same as there is always some residual oil left in the engine after it's drained.I agree, just want to know why they initially overfill at the factory.
BMW airhead boxer twins motorcycles are the same way. Once the sweet spot for fill was determined, I could fill to that mark and it would stay there. If I slightly overfilled, it would eventually reach that mark. It was never to the full mark on the stick.On a side note, when I was growing up, my dad had a 1971 AMC Gremlin. If you filled the oil to the full mark on that car, it would burn off oil until it reached the add mark, then stay there.