The different brokers use different data feeds from their Liquidity Providers. It may happen that some brokers use same LP, but most probably the data will be different. These difference reflects on the strategy performance. It is highly possible a strategy creates and tested on data from one broker to not work well on data from different broker. Even if two brokers use one and the same LP, the may use different time zones.
The Data Download service in FSB uses data from DukasCopy, which is the provider of jForex, so it must be no big difference between Download and jForex results. However, you are going to trade your experts on MT and your MT broker uses different LP.
The best practice is to use data downloaded directly from your MT terminal for creating strategies. It must be easier to export market settings and data files by using the scripts provided in the Premium Club (licensed users only). Two scripts are provided:
- MetaTrader to FSB Data Export
- Export Symbols and Settings from MetaTrader