Let’s say you want to give a 20% discount on shipping when the cart subtotal is over 100USD. With Handling Matrix you can do this. You can even vary to give a 40% discount when over 500USD.
Use the PERCENTAGE_SHIP algorithm to implement.
Row 2 in the above csv file is saying that when country is USA and cart price > $100 then discount the shipping by 20% of the cart price.