This is what I was able to find in a certain online database. It was relating to a GL trx in a year that was Temp Closed, but it was the closest answer I could find:
(I am no Macola financials guru by any stretch so please proceed with caution and at your own risk)

"Yes. As long as the System Periods for General Ledger are not marked as Prevent for Transaction Not in Current Year, Progression will allow an entry to the prior year. For Example: If the GL System Periods are set to the calendar year 2008, an entry made with a transaction date of 2007 will post to that 2007 date. Also, the Comparative information for that account for 2007 will be updated for the appropriate period. If the GL System Dates are moved back to 2007 and an entry made to 2007, the Comparative information for that account for 2007 will not be updated.

In either scenario: Any time the System Periods for General Ledger are moved back and forth between years, or an entry is made to a past year; it is a good idea to run the GL, Process, Recalculate Account Balances so financial statements will contain the correct information."