Possibility to enforce invoice matching (and discrepancy approval) when adding extra lines during the purchase invoice process.
Currently (assuming that invoice matching is activated - 3-way matching enforced), if a user add a new line during the invoice process (ex: extra service invoiced by the supplier), the invoice matching is not performed and the user can post without further control. This is considered as by design from Microsoft, because the 3-way matching only applies when an invoice line is matched against a receipt. As a consequence, there is less control for an added line compared to a small difference of unit price on a matched line.

We would expect the invoice matching to be failed in such case, with required approval before the invoice can be posted.
Furthermore, the system does not provide screens or reports where such cases can be easily identified (as a mitigation for not having the control).