And for those of you who use TradeStation, according to epiktetos at
post 12637 the following is the info about upticks vs down ticks:
"TS uses the following rules when assigning a tick to the reserved word UpTicks:An uptick is a tick whose price is higher than that of the previous tick of a different price. Thus, if tick 1 occurs at a given price, tick 2 occurs at a higher price, and tick 3 occurs at the same price as tick 2, both tick 2 and tick 3 are counted as upticks."