Just out of curiousity does anyone else have this problem/question?

According to the specs, the fuel tank is supposed to be 17 gallons, but my fuel indicator is coming on at about 12.5 gallons. I have been fueling up for fear of running out of gas, but I really think the indicator needs to be adjusted.

Anyone else have this? And do you think it would be worth my time for a trip to my dealer?