mtgox does not what I tell it to do

[allocater]

So I enter: "buy at 15.2" and it buys at 15.2918.

I enter "sell at 15.7" it sells at 15.598.

  you can't explain that

[Grant]

Trading fees (0.65%)

The fees are directly charged into your trade, and don't appear as a separate line in your trade history.

[allocater]

oh, ok, I thought the fees were taken care of by the reduced bitcoin count. I.e you buy 1 and get 0.994