I can confirm that now there is a variable spread that changes from tick to tick. But anyhow there seems to be a problem anywhere. If I trade the simple broker arbitrage script in EUR/USD on 2 demo accounts over one week with a threshold factor of 2.5 there are 16 trades, if I test it with Spread=marketVal() over the same week there are 514 trades. I will verify it again next week and explicitely record and store the ticks of the accounts used and if those differences reappeared I'll come back with them in the broker arbitrage thread.