Forex Robot/Expert Advisor - increase the lot size

After deep thinking, I decided to follow the paln - to increase the lot size from 0.06 to 0.07 for the incoming week (week 9, 2010).As I mentioned before, I planned to increase the lot size 0.01 every week if the forex robot - Forex Transporter  is performing well.However, I am also worried on margin call as sometimes the Forex Transporter will open 2 active trades.Other than that, I am also