Griffen, if you read the post it states "maintenance". As my records point out, I have made 5 oil changes @$70 and a couple fuel filters @$100 a pop in the diesel. That works out to $550. The old ladys rig has had 10 oil changes @$30 each which is $300. So over 30K miles this is what it cost me to operate both. As stated before, the mileage is close to the same. When I "run the numbers", I figure out the fuel burn per 24 hrs at rated BHP, overhaul cycle, parts and labor to rebuild said equipment, break all this down to a cost per operating hour over a 10 year period. I do this at work and about the same for my own purchases. However, I know this isn't as accurate as scribbling down some chit on a note pad at the kitchen table trying to make the #'s work for the wife so she will let me buy it. B.