I use 1810x1018 w Black bars to get an effective 106.26° Hfov in Overwatch, and I was wondering if I need to also adjust the scoped sensitivity in order to get 0% Monitor match as the black bars are still present when scoped in.

 

I used the Geobra calculator linked in the Conversion method guide and set fov B to 51° the Hfov of Widowmakers scope and then moved fov A until the resolution matched the already set 1810x1018, giving me an actual scoped fov of 53.65°.

Is this the correct method to find what my effective scoped fov is ?

Could you explain that method to me and what is it for?
I am something new in all this