17 mils is .17/100 shares. Stocks are quoted in .01, or $1.00/100 shares . So, 50 mils, or .005, round trip would be break even if you buy a stock at 20.00 and sell it at 20.01. 25 mils, or .0025, is a good rate, but it relates to .25/100 shares, not 1000 shares.
I could be wrong, I still...