Scales discount as separate line item

Our primary goal is to maintain "one price" even when you receive a quantity discount (via scale factor). So we want the quantity discount to "live" on it's own line item. This also needs to be material specific (based on quantity or value) not a blanket discount at the header level.

What we want to avoid: 1st order - quantity 10x$10 = $100 (price is $10/each) 2nd order quantity 20x$9.50 = $190 (price has changed to $9.50/each because of scales and quantity discount)

What we want: 1st order - 10x$10 = $100 (price is $10/each) 2nd order quantity 20x$10 = $200, but now a "discount line item" is automatically generated which is separate from the material line item which shows "discount" = -$10. So the "price" is the same at both quantities (and the customer can't complain about the price changing), but you get a quantity discount.

So we avoid the irritation of seeing the price fluctuate, but we promote the reward of ordering larger quantities.

Every answer I have seen for complex examples of scale factors always results in the line item price changing. I can't find anything where a new discount line item is automatically generated at certain price/quantity thresholds.

Thank you for any help!