Yes, that is why. Same with my wife's car. On the open road she gets 32 mpg. Her round trip of a whopping 2.3 miles yields 17 mpg. But she only fills up once every two months so it evens out. I take it out on long runs once a month and/or drive it on my 80 mile round trip commute to "blow the cobwebs out" and I change the oil and perform maintenance on a time schedule instead of miles.
2013 V Star 1300 Deluxe
OEM Tall Sissy Bar
Memphis Shades Fork Deflectors
Bridgestone Exedra Max Belted Tires
Baron's RSTD 7308 bar