We use average costing for virtually all of our item sites. "Standard Cost" is almost meaningless to us in our implementation, but it's used everywhere in xTuple.
I would like to synchronize the standard costs with the actual costs using trigger functions on the itemcost table. When the actual cost updates, so does standard cost, and all of the locations where standard costs are show, they will match the actual. Is this a bad idea?
Similarly, I'd like to automatically roll up actual cost on affected items whenever a costing element changes, but I haven't thought that one through yet.
Last comment: it should be possible to turn off the "Standard Cost" paradigm in the system so that wherever "Standard" exists, we can see "Actual", if that makes sense.