Clarification Arbitrary Surface on Shelf

[adriankoering]

An arbitrary surface on the shelf might only be on the upper or the lower level of the shelf. In this case the Shelf as a workstation would have an arbitrary surface according to the ref sheets resulting in additional points for both pick and place with either pick or place being without enhanced difficulty. This should be defined more clearly, either by placing the arbitrary in both areas always or by defining the two shelf levels as individual service areas/workstations.