in reality, you will need a 3/4 pt move to scalp your 1/4.
say, the market is trading at 1330.00.
you can't just buy at 1330.00. Nobody will sell it to you.
you have to bid 1330.25.
ok, you have bought at 1330.25,
the market moves to 1330.50, and you want to sell at 1330.50.
well...