you are missing something with the optimization.
The first time you did it with step of 1, and the second time with step of 10.
It is good to do optimization with round numbers as step. But make sure the parameters of the strategy before the optimization to be round as well.
For example, make Stop Loss 80 and Take Profit 70, and then do optimization with step of 10. Same for the other parameters
Your Monte Carlo is just fine. The over-optimized strategies will show total loss with all tests, which is not your case. And yes, you are correct.
No weekend for me during the last years, mate 🙂