I've been thinking about this gallon marker orientation issue for a bit. And to me, it makes sense to have the cylinder full before starting with the number 0 thru 10 starting with zero at the top. My reasoning for this is because sometimes you don't really know how much gas your tank is going to hold. If you had it the other way around you may fill the pump cylinder up with 5 gallons and then begin to fill your tank.....only to find out your tank will only hold 2 gallons. Yes you can do it that way but you'll have to do a little math etc. However, with the pump cylinder full before you start to pump it in your jalopy the cylinder level only drains down to the exact amount your tank will hold, and the level of gas left in the cylinder indicates the exact amount of product you are buying on the markers. This is my first post and I hope I'm not embarrasing myself!