I would argue fuel is one of the most variable costs between operations.  If diesel is used for irrigation and you go through 25,000 gallons of diesel/summer that adds up.  The guys that are full tillage probably use twice as much diesel as the no-till guys.  Some operations do all their own trucking.

I don't recall the last time I booked diesel fuel as I generally just fill when needed. I can handle 2,500 gallons at a time.  Some years I use 6,000. Others I use 8,000.  Sometimes I win, sometimes I loose.  Right now the local truck stop is almost $1.00 cheaper than the coop......I'm tempted to take my portable tank there and fill it up with clear.