As I think understand it, when you are in a trade in a pair, neither of which are your deposit currency you have effectively gone short your deposit currency.
You are exposed to 'cross currency risk' that your deposit currency will change relative to one or both of the currencies that your trade is in. I think this is expressed in the MarketInfo(Symbol(),MODE_TICKVALUE) function.
Am I talking nonsense so far?
If the above is true. Does MT4 strategy tester factor in the constantly changing tick values? It would need a tick value for each bar similar to the OHLCV array for each bar.
If anyone could shed some light on this, I'd be very appreciative.