That's still ok. Pump gas doesn't read like race fuel which doesn't read like alcohol. Even different fuels from the same manufacturer don't always read quite the same.
That short plug and ground wire with pump gas means you read total timing closer to the shell. If you had a projected nose plug, I'd say reduce the total until you move the mark up the ground strap from the shell to ~.080-.125ish.
BTW, why are you using a short reach plug? If the piston isn't in the way, you may be better off with a projected nose plug.
