8BA valve seat grinding

[61Klassic]

Hi. I’m in the process of grinding my valve seats to set the lash as I have non adjustable lifters. Due to the fact the valves aren’t at 90 degrees to the deck, my cutting tool is creating a larger valve seat contact area towards the piston as it is obviously contacting this area first.
Could anyone advise if this is correct or what I need to do to rectify the issue.

Thanks in advance for any help
Kev