outside operations costing

["Chick Doe" <Cdoe@xxxxxxxxxxxxxxxxxxxxxx>]

here's the situation:

bpcs version 6.1.2

we cut a work order to produce some parts. one of the operations is a heat 
treat operation that must be done outside. the heat treat vendor charges us, 
not for the number of parts that he treats, but for the each heat treat cycle 
that he performs. thus is we send 1 part out he charges $200 (example cost). if 
we send 100 parts out he charges ($200).

questions:
1. how do we set the outside processing cost in the routing operation record 
(my guess is to determine the average number of parts processed at a time and 
divide this into the lot charge to determine an average cost per part)
2. how do we write the OP Purchase order. we have been trying to figure out the 
actual cost per part for each batch by taking the lot charge and dividing it by 
the number of pieces being sent outside. but because the number of parts 
changes from batch to batch., this results in numerous PO's for the same 
process, each with a different PO price. (this takes some persistence to 
explain to the accounting folks.) it would be nice if we could write the PO 
stating one lot for a total charge of $200, but how would this interact with 
the work order qty completed?
3. how should we record the variance between the 'standard cost' of the op 
operation in the routing record, and he actual charges from the vendor?

thanks in advance, just another day in the interesting world of cost accounting!

chick doe
barton instrument systems