I've just tested code developed in Zorro 1.46 on Zorro S 1.54: history data is the same, code is identical. In 1.46 it has a win rate of over 60%. In 1.54 with the code unchanged it drops to below 55%, which is not even break-even on an 80% win payout.

In the results .txt, there is a difference in
1.46: Simulation mode assumed slippage 10.0 sec
1.54: Simulation mode Realistic (slippage 5.0 sec)

If I change the slippage in 1.54 to 10, I get even worse results. Changing it to 0 and I only bring the win rate up to around 57%.

What gives? Has something changed in the way Zorro backtests binaries to cause such a significant difference? Is it just default settings I'm overlooking or some significant change? I have been running this code live for a few months and been making profits from it, but now I'm not even sure what to think.