Quantity invoiced greater than goods receipt quantity (& &)

What causes this issue?

This message can appear for two reasons:
The quantity for which you are entering the invoice is greater than the
difference between the quantity delivered so far and the quantity
invoiced so far.
The invoice refers to a service item for which an invoice has already
been posted.
IF &[SWITCH]S4H_DOCU_ON_PREMISE& = 'X'.
INCLUDE MM_IV_MELDUNGEN OBJECT DOKU ID TX
ENDIF.

System Response

The system has determined that the product of <ZG>(invoice quantity -
quantity to be invoiced) * order price</> is greater than the tolerance
limit for quantity variances
IF &[SWITCH]S4H_DOCU_ON_PREMISE& = 'X'.
This tolerance limit is set in the Customizing system.
ENDIF.
In the case of order-based Invoice Verification, the system blocks the
invoice for payment at the time of posting with the blocking reason
"Quantity variance".

How to fix this error?

Check your entries and make any necessary corrections.
Goods Receipt-Based Invoice Verification
IF &[SWITCH]S4H_DOCU_OFF& = 'X'.
Conventional Invoice Verification
The system does not allow you to post the quantity entered. For this
reason you can only post the invoice as a subsequent debit/credit. If
you want to do this, enter the appropriate subsequent debit/credit
indicator in the field <LS>Subseq. debit/credit</>.
ENDIF.
If you post the invoice despite the variance, the system carries out the
posting and the associated account movements. However, the document also
receives a blocking indicator, so that the system cannot pay it.
Order-based Invoice Verification
If you post the invoice despite the variance, the system carries out the
posting and the associated account movements. However, the document also
receives a blocking indicator, so that the system cannot pay it.
Invoice for a Service
A service item is considered to be completely settled when the first
invoice is posted. If you receive another invoice, as in this case, you
can only post the invoice as a subsequent debit/credit. Enter the
appropriate subsequent debit/credit indicator in the field <LS>Subseq.
debit/credit</>.

Error message extract from SAP system. Copyright SAP SE.