Based on my experience of dealing with the IRS for many years, the IRS has put all the bills belonging to the VAT input tax in charge, is the acquisition of invoices is an exception. If you don't believe me, you can see such as freight invoices, waste materials invoices, customs VAT payment letters and so on.

They are now the most headache is this acquisition invoice, on the one hand, is filled out manually, on the other hand, due to the amount of quantity as well as the seller of many customers, so they are also thinking of countermeasures, and gradually stop the issuance of acquisition invoices, most of which have been canceled the manual version of the acquisition of invoices for the receipt and fill out. A part of the region has stopped the use of the computerized version of the ordinary acquisition invoice.

The future trend is to use the network version of the acquisition invoice, so that when the enterprise uses each acquisition invoice, the tax bureau will grasp and monitor the input in real time.

I don't know if this explanation will satisfy you.