How to deal with "remnants" in consumption?

Hi,

We buy standard bars that are 12 feet long, and we cut into pieces that are 5 feet each and call them ribs.  So each bar can make 2 ribs, with 2 feet left over.

If we have requirements for 6 ribs, SAP tells us to buy only 5 bars, but we need 6 because we cannot use the extra 2 feet left over from each bar.

Does this scenario make sense?  There has to be a way to set up the Material Master to understand the remnants can't be used.

Is this more of an MM question than a PP question?  I wasn't sure where the best spot was for the discussion.

Thanks!

Timothy