Item is set with fixed receipt. Cost on item card is $10. Received at $12. $2 posted to loss. All guess work, memory says it works that way, but the best way is for you to actually try it.
Create an item with a standard cost of $10 at site 1 and $9 at site 2. Transfer it. Posts to inter accounts. Although it maybe that it is weighted average and you have the dimension group to financially cost by site, in which case again you will have to try it, load up something with a difference and transfer it.