Is Conversion to Reporting Currency Possible with 2 Different Rate Types?

We are setting up a new USD Primary Ledger which is the first overseas ledger for an Australia-based organisation.  Our Finance department want to report all activity, both at transaction level and GL balance level, in AUD so the first thing I've done is to create a reporting currency as follows:

Primary Ledger: US Ledger

Currency: USD

Reporting Currency Name: US Reporting Ledger (AUD)

Currency: AUD

Currency Conversion Level: Subledger

Default Rate Type: Spot

Retain Transaction Rate Type: Yes

This issue we have is that our Finance department want the reporting currency to follow normal accounting standards and post to the P&L using the