One of the features which didn't make it into LedgerSMB 1.3 was extending the separation of duties interface to include invoices which might include inventory. Separation of duties in 1.3 was there, but it did not extend to cases where there were inventory movements.
The wait will end with 1.4 which extends the separation of duties structures to invoices with inventory. With separation of duties now, invoices will post when approved rather than when saved. This also makes it reasonable to delete and edit the invoices between saving and approving.
One of the big differences however is that cost of goods sold is now calculated at approval time on FIFO basis rather than at invoice creation time. Consequently if an invoice is delayed in terms of approval for an extended time, this may affect COGS calculations This is unlikely to have significant effects between accounting periods but it could cause minor effects if many invoices from an old period are not approved until after many invoices from a new period (in times of price instability).
This feature gives LedgerSMB users, for the first time, the ability to have all financial data entry performed by users whose work must be reviewed before it becomes a part of the official record of business.