NLAG can in general have any view you select in OMS2 customizing, even such views which do not make any sense like storage location view, since NLAG itself is just a name and the consultant defines the attributes to this name in OMS2.
If your NLAG does not have an accounting view and you create a requisition with ME51N then you have to enter the value yourself .
If you get a value automatically in ME51N despite of the fact that no accounting view exists then there must be some manipulation through a BAdI or exit.