I filled up my '07 Edge today after my "low fuel" light came on. I filled up with 15.25 gallons. Wondering what exactly the fuel capacity of the car was, I glanced at the window sticker that I have in my information pack. The sticker says that I have a 19 gallon fuel tank. Is this correct? If so, why is my "fuel level low" light coming on after going through 15 gallons?