It would be desirable to see in the invoice not only the invoice amount, but also the sum of outstanding receivables from previous advance invoices that may have been paid in part.

example:

Then for the 3rd AR:

Invoice amount 100,000€

Outstanding receivables from previous AR 30,000€

Total invoice amount + outstanding receivables 130,000€

Although the outstanding amounts are shown in the benefits appendix, the sum “claim amount” directly below suggests that the outstanding amounts could already be included in them.