Clarification on Default Translation Method Setting

Summary:

We have a requirement to translate P&L accounts based on YTD translation method. (Entire YTD amount is translated using the current period average exchange rate). Can this be achieved by changing the Default translation method of Flow accounts to 'Year to date'?

Currently all the P&L and Balance sheet accounts are defined as Flow accounts in the system. Does the Balance account setting (in Default translation method) applies to Balance sheet accounts and Flow accounts applies to P&L accounts? Or when we change the Flow account default translation method, it applies to both P&L and Balance sheet accounts?