Ordered quantity VS billed quantity

Hi,

i need help.

I have to make a report which display ordered quantity VS billed quantity based on some selection: order creation date, sold to party, order number, billing number.

For this I used table VBFA but it's a bit complicated if a sales order contain returns or if a position from sales order contain multiple billing.

Is there any bapi function ?

Any advice is welcome.

Thanks in advance.