Hi Timothy,
What do you do with the remaining bars (I mean remaining 2 ft every time)? I assume it is scrap. And I assume 2 pcs each with 5 feet is called one rib. In this case please maintain assembly scrap in material master as 20%. This will be considered in MRP also and you will get planned order of demand qty. But when you will convert the planned order to production order, the scrap/extra qty will be considered.
Ex: Assembly scrap 20 %
Requirement 100ft.
Planned order 100 ft after MRP
When you convert it in prod order, it will be 120ft.
Regards,
Krishnendu.