can someone supply a little more info on this please?

I am waiting for my £1000 day trading pot to arrive at mtgox (i already have some long term bit coins). I assumed that after the receiving fee, all i would be charged is the 0.6%. Which if I do a quick buy and sell would cost me £12 total.

However if I'm also losing an extra £25 in each trade, this is a huge amount. (£62 for each quick buy/sale?)