In the script Workshop4_1 I set slippage = RollShort = RollLong = 0 and compared the profits from Entry-Exit-TradeCosts with the profits Zorro displays and found the same deviations. It seems that they increase in percentages with the profit, at a profit of 60 e.g. the deviation is about 13 %. The calculation of the TradeCosts is really okay the way it is in the manual?