Zorro uses Ask prices, but that is just a convention and does not affect strategies.

Your system can never trade because High(0) can never be lower than Low(1) on hourly bars. Currencies are traded 24 hours, so you would only get trades with this system when you used price data with gaps or missing prices, and then the result is random. The price data that we deliver with Zorro reflects the 24 hours market and has no gaps.

The original idea of this system was possibly using the open and close hours of a certain stock exchange for determining High or Low. That would make sense, but only when trading once per day, not once per hour.