NO. The ping happens in real time. The aircraft was on that arc somewhere at 8:11 AM. There is no margin of error.
There is a margin of error on the final resting place for several reasons, the biggest being that there is no way to know how much fuel was left after the last ping. Sure the plane must have been very near that arc @ 8:11 but then there is up to 59 minutes more fuel to burn plus glide time.
Y'all might be talking about 2 different things. One thing is where the plane was @ 8:11 which is very near the arc. The other thing is the final resting place of the plane which could be hundreds of miles away from the arc...