Strategy Tester: data consistency

Hi All,

I've imported my own data into MT4 and I'm running simulations using M30 and the "Every Tick" method. Basically it seems that the strategy tester generates data outside the High/Low range????
For example I can have OHLC M30 (from my own source) like this:
14:30:00 - 14:59:59 1.3535 - 1.3540 - 1.3530 - 1.3537
but when I run simulation I sometimes get a trade executed at 14:35:00 at 1.3542 which is above the High for the given period.
It sounds like either MT4 generates random tick which I can't believe or it get tick data from my broker which is obviously different from my third party source?

I would be happy to know if someone came across the same prb and what is the conclusion you came to?

Thanks

Long position enters at Ask price that can be higher than High by spread value.

Thanks for coming back to me. That sounds sensible.
Is there a way to know exactly where this value comes from / how it is calculated?

Cheers