E9 Product configurator postings (costs) to GL

We use product configurators to create bespoke products, costs for these configured items are variable therefore we do not use standard costs against the configurator parts. This results in, the system does not recognise the costs as part of the job and treats it as a variance (not carried across with the invoice). This means end of month lots of matching up and it also eliminates AR Clearing functionalilty as the 'variance' as it sees it, posts directly to cost of sales. Has anyone else experienced these issues? Any suggestions on how to fix this would be appreciated!