Currently there is no provision in D365 finance to use different exchange rate types for subledger revaluation other than set for the entire ledger via the Accounting Currency Exchange Rate Type field, via the Ledger set-up page. When subledger revaluations are performed, they use this rate by design. We have customers that want to use a different exchange rate type for operational transactions posted in the ledger vs those used for subledger revaluation.