These are typical results. I make networking equipment that has to deal with wireless connections. Our tests are as ideal as you can get without driving around for a tower and sitting under it (although we have done that, too). We're typically in an office, stationary. This means no tower hand-offs, and stable (relatively) conditions. Round-trip-times in the 20 sec range are not rare. I've even seen RTTs a minute long several times, and once saw even greater than 90sec.

What is really interesting is to watch the RTT while you run a speed test.