sales order and delivery qty

The sales oreder # has a material to deliver it's requirement is 8400 and the stock is good but q"ty of 340 EA has not been picked up ...

IN the Delivery the Qty picked uo is 8060 not 8400.

but the order status in now fully delivered

any body can answer what is exact issue there an dis there any setting have to be made as there is no partial delivery in order but delivery qty is less than order qty.

if want more info pl let me know..

Regards !

Vaibhav