This test has been duplicated many times and is known phenomenon ...indicating the time is relative and varies depending on the effect of gravity..Arrgh..I can't explain it right.
I met a guy who had a precise sense of time. He said it came from watching episodes of I Love Lucy as a child. Each episode was exactly 30 minutes long. He learned to stack 30 minute intervals. He said that up to about three hours after seeing a clock, he could tell you the time (assuming that clock was right.)
My time-sense is very elastic. I thought everybody was like that. In fact, I wouldn't have believed the dude had that ability if I hadn't seen it demonstrated. Precise time-sense is as astonishing to me as perfect pitch.
The moral to the story is: people don't experience the world in exactly the same way. Your way may be unique.
I don't answer it...hence, the non-relative state of my existence.
I have a bit of understanding how time is relative.