Comcast Testing Higher Speeds?

My Internet experience has been bumpy all day, even though my connection speed was far better than expected. I don’t think the problem was speed as such, it’s was the spottiness – lost of 1-2 second mini outages. Now I’m starting to wonder if Comcast is silently testing a major speed update. Just looks at these test results:

That’s quite unbelievable, it’s about 4 times faster than Comcast’s stated speed. Can anyone confirm / deny? Rumors?