Not necessarily. If I get a deal, $100 of stuff for a few bucks, or get it free from grandma, I have instant wiggle room for pricing. Or iff I buy 500 doilies for a song, it is further incentive to move them out below "market value" because no matter what I sell them for, I have made a huge profit. I might use a sale, or BIN or MAO.
In this case I would not be using MAO because I did not know the price. Or because I overpriced my items. Or because I want to devalue my stock or this site. I just have lots of stuff to sell, I bought it for rock bottom, and can afford to be flexible. I think alot of buyers are like that.
Market values vary, they are not constant in this economy. Good sellers take advantage of brisk markets, and attempt to stimulate slow ones by changing their prices. Sometimes they are forced too when certain items just do not sell well or have lost value in this economy (furniture for example).
Most sellers realize this so If June is slow, they have a sale, offer more BIN or MAO. They figure, either sit on all your stock and wait for that high price that it is supposed to be worth in an ideal market, or sell it cheaper and make only 400% instead of 500%. I tend to think most sellers are in this group so the MAO would add to their flexibility to sell based on a changing market.
Again, just to defend myself, I probably would not use MAO, but that does not mean anything at all.