How do you overwrite a system translated balance in ARCS?

For testing purposes, we are trying to import reporting balances (USD), from a different system, into ARCS. We are importing balances for individual and summary reconciliations. For International account profiles, on the currency tab, the individual accounts have historical data as the rate type and the primary and secondary ledger's checked. The summary recs have EOM or AVG rate types, depending on it the account is a balance sheet or income statement account, and the secondary ledger checked. We tried to import pre-mapped balances, but the imported values did not overwrite the existing balance, but just added