Not able to perform f.13 due to difference in DCIR

Hi,

I am FI consultant and having the below issue. please share
your experience on this

For the Quantity 100 they have done GR&DCGR. The same
100 quantity they have done IR. but they did not done for DCIR. Later for the
quantity 50 they did DCIR.

Now they perform F.13 but they are not able to perform this
activity due to difference in DCIR. That is 50 quantity. We need to clear by
posting an invoice for this quantity. But we don’t know how much price we have
to post for this difference quantity.

And also there is price difference in GR and IR .Then how to calculate price for remaining quantity 50 and suggest the user to post this difference quantity.

I have a question is there price difference come when we generate invoice for delivery
cost to vendor. Please let us know .

Thank you

Regards

Rajesh.P