We want to use our own specified Fx rates for our transactions.
The default exchange rate that Intacct uses is called the Intacct Daily Rate. This rate comes from Oanda.com and is calculated using an algorithm that takes the average ask rate for the entire day's transactions. Therefore, the Intacct Daily Rate for a specific day is actually the rate from the previous day.
However, custom rates can be setup and used in place of the Intacct Daily Rate. Add different exchange rates in Company / Setup / Exchange Rate Types. Then maintain those Fx rates in Company / Setup / Exchange Rates.
The default exchange rate type that is used in individual transactions can be set in Cash Management / Configure Cash Management in the Accounting section. However, during each transaction, the fx rate can be adjusted by clicking on 'Show Details'
and then editing the value in the Exchange Rate field: