The bar stock that left the store and did not come back

A job needs a metre of bar. Two metres are issued because that is the length available. Eighty centimetres come back and go on the rack, and the job carries the cost of two metres.

Two errors in opposite directions

The job looks more expensive than it was, which distorts estimating. The store thinks it holds less than it does, which triggers unnecessary purchase. Both come from recording the issue and not the return.

The rack is inventory

Offcuts have real value and are usually treated as scrap-in-waiting because nobody can find a particular size when it is needed. Recorded with material and dimension, they become the first place to look before ordering.

Why it is worth the discipline

In shops working expensive alloys, offcut recovery frequently exceeds the value of any efficiency improvement available on the machines. It is also cheaper to implement, requiring a record rather than capital.