actually keeps the PPS up at the ask, usually that does help it from retraceing , but people get board and attention fades when price doesn't fluctuate, sometimes retraces are nice because it brings in new buyers and more attention. forceing the pps to stay at the ask also stops shorts from being able to cover at low prices
There are people that are trying to sell there shares at the ask price. When someone is selling on ask and they get a fill for 100 shares, they may get pissed off. It happened once today and that person moved. It cost him $10. to get $1.50 worth of shares.