The "Force Index" is calculated by subtracting yesterday's close from today's close and multiplying the result by today's volume.
Force Index use the tick Volume for the calculation. The different brokers use different liquidity providers for the market data, but they are more or less the same or very near. On the other hand, the tick volume is very specific for each broker, data server or account type. The volume may greatly vary from account to account and it makes it difficult to compare.
If you want to create a strategy that works on different data sources, please use indicators that are based on the market price only. You may uncheck the "volume" indicators from "Tools" => "Available Indicators".
I'm going to make the "volume" indicators unchecked by default in the near updates.