How to get accurate financial statements and adjusted trial balances with multi-currencies?

Hello, 

I'm having some issues with the multi currency feature at the moment of using the report "Adjusted Trial Balance". The company where I work has a branch in Mexico and uses the MXP currency, so after the end of each month, there's a "Exchange in Gain and Loss" where our USD bank account is affected. 

Example, at the beginning of the period I start with $1,000 USD in bank account "A", and the exchange rate in that day is $18.5 MXP, so my "Adjusted Trial Balance" reads: $18,500.00 MXP. But let's say that at the end of the month, I did not spend anything and I'm still with $1,000 USD but now the currency has changed to $19.0 MXP. So, how can I change the value in my "Adjusted Trial Balance" to read $19,000.00 MXP and having the same $1,000 USD?. 

I tried doing a general journal in exchange in gain or loss to match the MXP amount in  my statements, but my dollars in the USD bank account in QBs either increase or decrease, when physically my dollars are still the same. Hence, I cannot reconcile correctly either.

Does someone knows how to properly record this without affecting my dollars?

Thank you!