Thank you for your reply Santosh.
I still do not understand how I can handle the material issue at the beginning of the month as we issue a '0' value invoice with reference to the physical material numbers that we send out to the service centre at the beginning of the month. At the end of the month we bill the service articles which does not refer to the physical articles. Also It is possible that we may use multiple materials while providing one service and these materials may not be used in full for example for Interior cleaning & paint restoration service we may use 750ML of a 1Ltr bottle of paint, 250ML of a 1Ltr bottle of rustoff and 300ML of a 1Ltr of polishing liquid. Which means we may use one bottle of polish for 3 services approximately for example.
Thanks & regards,
Shiva