I have to agree, that doesn't look right. On my xfinity connection we get 60 down and 10 up. When tested it gets on average almost 58 down and close to 8 up.
A lot of results that are some what skewed will come as a result of time of day, location of server, and how much traffic there is on either end. I run my tests on the xfinity test page and in the wee hours of the morning when traffic is low on my end. I use Nashville or Little Rock servers. Houston always seems to be busy and gives skewed results.
XFINITY Speed Test