This note clarifies an important approximation used to simulate the breakdown field in the SiO2 liner of a SiC Charge-Sheet Superjunction - a new power device structure - reported by Akshay and Karmalkar (2020). This electric field simulation sought to assure that the new device does not suffer from SiO2 reliability problems. The note answers two questions: (a) Why do we remove the SiO2 liner which is the very region of our interest during device simulation, when a simulator allows inclusion of such a region? (b) How can one solve for the field in a region (SiO2 in the present case) by neglecting that very region during device simulations? Our note reinforces the insight - 'Modeling is the art of making approximations. © 2013 IEEE.