Unless I'm missing something, this can be handled just like a simple
checkbook balancing sheet.
Column A would hold the date of a transaction
Column B would hold 'deposits': quantities shipped TO the customer.
Column C would hold 'debits': quantities that they have shipped out that are
to be invoiced
Column D would then hold the balance on hand

Assuming row 1 is labels,
In D2 put this formula: =B2-C2
and a beginning balance would go into B2 and possibly a shipment recorded in
C2
in D3 put this formula and fill it on down the sheet
=D2+B3-C3
that will give you the balance on hand.

You can then use a variety of methods to determine the quantities shipped/to
be invoiced for at the end of any given month.
You can add a column for dates

"gritsgirl0430" wrote:

I have a customer that receives agricultural products on consignment. Once
the customer ships any of the consignment products at the end of the month
our company invoices our customer. So we have to keep track of what is
shipped to our customer's warehouse and how much has been invoiced. Thus,
removed from the consignment inventory.

Please help!