some how i think u over reacted, this minor difference cud have occured due to an un-even surface of the car.
As Hondas oil packs are of limited quantity (3.76 liters) and all of it goes in.
While the ones availble in the market (shell, caltex, etc) come in 1,3,4,5 liter packs which can cause access oil goin in the engine and mostly we save half a liter at every oil change. (in a 4 liter pack)