You can restrict delivery with delivery tolerance, thereby causing invoicing
of the desired.
Go to SPRO>>>IMG>>>Sales & Distribution>>>Billing>>>Billing
Documents>>>Country-specific features>>>Maintain Maximum No. Of Billing Items.
This is where you can define a maximum number of items allowed for all
billing documents within a given sales organization.
However, maintaining data here is not enough alone to bring about a billing
split by number of billing items.
You must also go to copying control for order/delivery to billing document at
item level under "Data VBRK/VBRP" and maintain routine 006 "individual invoice
limited" or a similar routine that accesses the data maintained here.