I have very few items with make an offer enabled.

As far as I'm concerned, given I actually research my prices, any offer is a silly offer. For a start they are unsolicited. The last one I had, the offer was for about 70% when postage was taken into consideration. He bought it a few weeks later at listed price. (I was the cheapest for this item (set of 3) anyway, so he didn't really miss out).