This input enables a currency balanced stop loss feature which groups orders profits by their symbol and then tries to cut a non-profitable order from one symbol with a profitable order from a different symbol which does have an equal or greater reversed profit. By assigning a value different than 0 to this input (the value should be positive) you are telling the expert to consider orders as non-profitable (and suitable for “cutting”) if their loss goes above the loss represented by this value.

For example, consider these two orders: BUY, EURUSD, +$60 profit and SELL, USDJPY, - $30.5 loss. Now consider that you set the Currency Balanced SL Max Loss input to 2, which means that the currency balanced stop loss feature will only be active for orders with loss greater than $20 (note that the loss is set as a positive value). With this configuration, the expert advisor would close the USDJPY order along with the EURUSD order because the USDJPY order loss exceeds the the $20 limit allowed for staying “untouched” and there is the EURUSD order with a profit able to cover the USDJPY order loss (ending giving a profit of $20.5).