subcontractring-variance calculation

Hi guru's

this is my burnning issue

my client is subcontracting the packing activity.SFG is issued along with packing material to vendor. After completion of packing activity FG return to plant.for FG we can create std. cost estimate and add sub contracting charges through additive cost estimate.here there is no production order.How can i value the FG and get variance analysis with out order.

thank in advance

Regards

SPSankaram