The field(Invoice Balance Impact) is seen under section 'Transaction(s) associated to this Invoice'. It shows the negative values of the Item adjustments made on that invoice.
This Invoice Balance Impact is generated by the internal query system that looks for all payment types tied to the invoice. That is how it generates the "Invoice Balance Impact" column. Unfortunately, this "Invoice Balance Impact" field is not accessible in report/datasource.
It would be great to see this field in the reports.
