you wont be able to override the Price using a Discount or charge rule, you will need to do that by crating a calculation on the calculation tab.
On the calculation tab create a new calculation named "holidayBasePrice" as:
[Price] = 35
This will set the price for any item added to the cart to $35
The create two charges to increase the price based on the quantity For 10 - 20 and another for 20 or more like you have below.