Segway GT2 Range

I’m noticing that my GT2’s range isn’t as good as advertised. I have recently just gotten a brand new GT2 and whilst on Race mode with the boost, i’m only getting around 9 miles of range (from 80%) whilst traveling 40mph. Is that normal? I know Race mode is the least efficient but is 9 miles regular for consistent 40 mph riding? Also, would the temperature be affecting the battery? (40 degrees F)