think at repeating fields like at nice tools to act a looping calculation or to show buttons and pictures; never think at them to store data.
So my thought is: use related table/s.
It sounds like you know what you're after and how to make it, so I'll not give Table/relationship details about how to do it unless you want them...but what you're describing simly BEGS for a ShipmentLineItems table.
Each good shipped (assume defined by product & Lot#) is shipped from an inventory record (key=InventoryID) against an order (Key=OrderID#) The ShipmentLineItems table thus becomes your join table, joining the inventory you're shipping from and the order you're shipping against. Unlimited line items per shipment, unlimited inventory transactions per product/lot, traceability to inventory, traceability to which order it went out on.
If you've already built in the function to see the sysadmin to add more shipments, it means you've already outgrown the repeating fields...use the join table approach instead. You can then even use the join table to print your paking slips/invoices/inventory reviews/etc.
Is this enough to start?
Thanks guys, I actually already have this tied to a template for our pack slips so it auto generates them, really got our company out of the stone age in the past few weeks. Anywho, I appreciate the info, i wasn't to firmilar with repeating fields but I heard about them used as an array in older versions.
Thanks to you ninja for the idea of putting my shipmentline table joined between the other two, didn't even think of it that way, was just going to have them all relate to the main table but your thought sounds alot more functional.