Beside which (one ought or any other subject as the context would provide) to keep a (separate) foreign exchange account so to [(facilitate the accountant when settling the account)/(make it more convenient in the account settlement(reconciliation) process)] to take into account of foreign exchange losses.

I think the Chinese sentence was saying that "if a separate forex account is kept" then either "the accountant" would find it easier to reconcile the accounts "taking into consideration of any forex losses" or that the "account settlement process" would be facilitated. I am not sure as I haven't worked in accounting for a long time and cannot be bother to check out furthermore. Hope this still helps. :)