[1] If the production and material flow gets more and more complex then more counting points must be installed in the process of transport, shipping, and manufacturing.
For better planning and monitoring of material flow items it is helpful to order all counting points in such a way that the requirements of an ideal Boolean Interval (mathematics) Algebra can be fulfilled.
Such an interval can represent any kind of stretch in production and material flow e.g. an assembly line, a storage or warehouse, a transport route etc.
Alternative production and transportation stretches are mapped as parallel intervals, which are logical equivalent but have their own different data acquisition points.
Other well-known counting points are receiving and issuing material items at the border of a storage or warehouse.