MTO free material

Hi all

For an MTO sample/free material which is not valuated, i want to create a new requirement class which is special stock E (customer stock) but without any account assignment and costing.

A) It appears that I could leave the costing and account assignt tabs blank ( any comments on this for feasibility or implications)

B) In the transaction OVZG, the field 'special stock' is grey and not ready for input. ( Main issue)

Thanks in advance for help.