I have a question about my full tank size, Jeep is 2015 JKUHR. The build sheet states it has 22.5 gallon tank. Then under optional equipment it states “5 additional gallons of gas” does that mean it has a total of 27.5 gallons? If so how does that work? When the tank gets low (with low fuel light on) and I put in gas it only tanks about 17-18 gallons of gas and the needle is basically on ”E”. If there was a total of 27.5 gallons seems like the gas gauge would not be on “E” at 17-18 gallons. The typical fill up is 16-17 gallons. Is there a separate 5 gallon tank? And no I don’t want to run it to empty to find out.