I understand what you're trying to achieve but from what I have tested, it's all possible except for showing a total for each individual invoice.
Please see below what I've done: 1. Reports > Custom Transaction Detail Report 2. Modify Report 3. Columns > Item 4. Total by > Customer 5. Sort by > Num 6. Select the 'Filters' tab 7. Select the 'TransactionType' filter and from the drop-down menu select 'Tax Invoice' 8. Select the 'Paid Status' filter and from the radio buttons select 'Open' 9. Click OK
The report will then generate every open invoice with each individual line on the invoice, but it will total every invoice by the customer, instead of each invoice. I can't see a way for it to total for each invoice.