Auto Invoice - Ship Date Actual

We have an order type where only when all order lines are fulfilled, the order will be eligible for interfacing to AR for invoicing purposes.  The order lines can be fulfilled on different dates for various reasons.  In other words different order lines could have different ship dates.  But when auto invoice is importing it is putting the transaction date of the invoice as the earliest ship date which business does not want this.  They would like to see the latest ship date.

If members can share their experience how they handled this requirement/resolved this will be greatly appreciated.