There is a good reason to adopt new method.
The more transactions you have, the more difficult it will be reconcile Qty to deliver and Qty to receive if something doesn’t add up.
Because if something doesn’t add up, you will be confronted with every single sales invoice and delivery note from the beginning of time trying to figure out what exactly was (wasn’t) delivered.
The new approach is to break this down into separate sales orders (units of work). Qty to deliver is the sum of quantities to deliver across all sales orders. If something doesn’t add up, you will see which particular order wasn’t delivered (or was over-delivered). Easier to reconcile with customers too.
I know it’s a bit extra work because if you want to track Quantity to deliver, you need to start using Sales Orders. But it shouldn’t add any extra data entry since you create sales order, then you can Copy to new sales invoice and new delivery note.
If you think the benefits do not justify the extra step that is now required, I’m always interested how the workflows can be improved.