Dual Unit of measure

Hi

I'm reviewing the dual UOM functionality and I have a doubt about it, i hope anyone can helpeme.

I ran an excersice with dual UOM item as follow:

- I create an item with conversion 1 EA= 100 LB)

- Due to inventory transactions I have 8 EA and 795 LB as secondary quantity  of the item.

- I created a sales order by 8 EA but the system commit only 7 EA (no backorder is showing).

- At the ship confirm, I send 8 EA and 804 LB causing negative inventory balance on the secondary quantity( -9).

- The inventory availability shows zero quantity primary on hand, - 9 LB on secondary quantity and a hard commit by - 95 LB on secondary quantity.