There is an obvious need for this.  Most large accounts payables systems have this feature.  You need to have the correct invoice date recorded for various reasons:  audit, communication with the vendor, to identify invoices that are consistently received late, imaging software will capture a printed invoice date.  It is a REALLY POOR BUSINESS PRACTICE to suggest that an AP clerk not capture the preprinted invoice date.  However, anyone can tell you that AP will always receive a few invoices after the period is closed.  So, you enter those items into the current period, but the invoice date remains the same.  In Oracle you have two date fields.  Invoice Date and Accounting Date.  If a period is open, the invoice date and the accounting date are the same.  If not, you need to enter a date from the open period (typically the data entry date)