Expense with Multiple currency not summing for check payments

When our users travel to other countries, their transactions are often reported in TXN_CURRENCY and paid in BASE_CURRENCY.  When they are being paid via check, the lines are not summing.  This causes the checks to go to overflow when it simply could be summed.

We found the code in the STAGE (EX_TRAN_PRCS) that is populating the EX_SUMM_PYMNT and are wondering why this is split out. Why would it not sum the transactions of same currency?

For example, if a user is getting paid in USD and has 10 rows on their report with USD, all 10 of those rows get summed to one line on the check, but if they have 10 rows of GBP and are getting paid in USD, the GBP lines get split out to 10 rows on the checks.