Column net price is empty

Dear expert:    

       By t-code me31k, Create 2 work contracts papers whose worldly radical successful interaction point are same. the worldly radical is 007 ( services ).  the antithetic is services maestro information of work enactment successful document，one work fig of declaration papers is 100225, the different work fig of papers is 100227.  then, By t-code me51n, Create acquisition requisition papers with worldly radical 007 ( services ) and work fig 100225. Double click "assign root of supply" successful root of proviso tab, the strategy amusement root of list, but I find that the file nett terms successful immoderate papers is empty. for illustration papers 4600000106， the nett terms successful immoderate papers is not empty. for illustration papers 4600000107.  

       Why the file nett terms successful this 2 papers amusement antithetic behaviors. Is this modular behaviors? I deliberation this is problem, could you delight cheque this occupation successful net sap system. surface shots is arsenic below.

Thank you