Hello Sarveswara,
Answering to you questions, B
Business Prospective: It could be possible vendor deliver to goods to out customer 80 instead of 100 quantity for which customer place the order. it could be intensely or un-intensely.
Suppose vendor delivery good to our customer 80 and send us vendor invoice of 100 qty. Now think about business prospectively. The customer received only 80 qty and after sending the vendor invoice by vendor definitely you will send a customer invoice to you customer with 100 qty. now Customer will accept your invoice ? NO, why he will pay for 20 qty which he has not received?. definitely, he will inform you that he receive only 80 qty and ask you to send correct invoice with 80 qty. Now you will go back to your vendor and cross check how much qty he sent to your customer. The vendor may accept is was done by mistake or may say send 100 qty then you can ask him for some proof to deliver 100 qty only, you may ask him documents like,shipping docs. and the truth will come out.
If Vendor has accepted that he has sent 80 qty instead of 100 qty to you customer then you may ask him to send remaining 20 qty or you can cancel you customer invoice then ask your vendor to resend correct vendor invoice with 80 qty. with reference to vendor invoice you can recreate customer invoice with 80 qty only
Technical Prospective: to avoid above situation you must follow Third party process with Shipping Notification.
Item category: TAS, Billing relevance: G
Copy Control: VTFA, Billing Qty: E
If we are following Third Party with shipping notifications, in this case, we can trace the goods movement for vendor, basically Shipping notification comes from vendor when vendor deliver the goods to our customer an Idoc triggered and send to us using through Idoc we can create good receipt MIGO, if vendor delivers 80 qty then MIGO will be posted with 80 only and taking the reference of MIGO/MIRO we can create customer invoice with 80 qty.
I hope above explanation clear your doubts.
Thanks,
Prashant Sharma