Have about 8 K miles on my TCH. Have never let my tank go lower than 1/4 to 3/8. Main reason, don't like seeing the 30 to 35 bucks going onto the credit card. Most gallons put in has been 10.6 on several occasions at the pumps. Then to figure just how many more miles the tank could have gone is to take the remaining fuel left in the tank (10.5 subtracted from 17.2) and use the mpg figure on the MFD or calculated mpg, to figure how many more miles I could go. No worry about an embarrassing run out of fuel situation or paying the tab for 16 or 17 gallons of fuel.

That is my way of thinking. But do think it would not be a legitmit claim to a 650 or 700 mile tankfull.