Huh??? In the "Megapack" the brush costs Fr. 10 -- and in the 8-pack Fr. 5.95! What kind of logic is that?

What I don't understand about this quantity discount is that two such two-packs cost 52.40 together and that is then advertised with three discount percentages compared to the individual price, instead of simply switching directly to the four-pack, which costs 38.30, which means almost thirty discount percentages on the individual brush and even less packaging waste. What is the point here?