Hawaiian flight arrival discrepency

I was watching Hawaiian Airlines flight 36 from Honolulu to Phoenix last week. Each day, flightaware.com reported it landing almost an hour early. My brother was flying that flight last Friday so I was interested in how the timing would work. I checked flightaware.com at 10:00 pm MST on Friday to see how the flight was progressing and it reported that the flight landed at around 9:30. Looking at the flight log, however, showed that the flight was still at FL390. He actually landed almost on time around 10:40.

So why the big discrepency?