How can I create a report to show which items I have actually invoiced in a certain period. So not sales order, sales by item as that only shows how many ordered-  but invoices. Why ? I hear you ask.  I want to see how many of a certain. item I have actually invoiced that day- not how many sales orders have come in, but how many I have actually 'sold'

For example:_ I have over 500 of a certain item on back order to over 100 customers from the past 6 weeks. There has been a stock delay. The inventory finally comes in today - 400 pieces. So there is not enough for everybody,. So I have to allocate them in order to be fair to each customer, and some people at the end of the  queue will not get theirs. 

I search (with great difficulty) for all the sales orders that are partially invoiced that contain that item, and work my way through the list ( it would be so helpful if one could just drill down into committed stock for that item but I have asked that question before!!!)  

Anyway, I gradually create invoices for each partially invoiced sales order and allocate stock. However, because Zoho  annoyingly doesn't remove items from available stock until actually shipped ( it would help if it removed when they are packed/ invoiced)  I have no way of telling how much stock I have left, until I physically start packing. This does not make sense- I want to  prepare all 100 + packing slips before I start packing, but because the stock does not update after each invoice and packing slip is created, the system may  allow me to  sell/ give in excess of the 400 that came in. I only discover the problem  either when I physically start packing, and realise I have run out, or when I go to ship them!! So, this  means a) I have to pack in strict date order (which is annoying as if one customer has several back orders I cant put them all together and pack them and I have to pack them in turn) and b) it also means I have no idea how many I have sold. 

So I need a report when I can sort  'invoices by item', filter by the date and  see how many I have invoiced so far that day, and whether I can keep creating further invoices. Or else I need you to make it possible to 'remove inventory from stock' at the point of creating invoice/ packing slip, so that the stock diminishes as I work through the back orders.