Hi Jeanette,
We use orders as well as fulfillment orders and SOP is posted by batch. The billing users are advised to change the transaction date to the date the transaction is fulfilled. If not we will have transaction dates and posting date being different. There are instances where the user may not change the date, but because the posting date is used it will go through.
Periods outside of the current period are usually closed, so anything outside the current period will not go through.
If you change to post by transaction the posting date on the batch will be greyed out.
I tested the conversion of a fulfillment order to invoice, I did not change the transaction date, but, it did not pick up the current date, it kept the initial date.
If you have a test system you can put through some transactions to determine what is best suited for you.
Hope this helps.