With the right conditions that doesn't seem crazy to me at all.  We did 285 acres of seed corn with a 16 row running a 15 row swath on two different field with an 8 mile move, refuel, added seed about 6 times and fertilizer twice.  It was a 13 hour day.  If the operation in question was on mile long rows with not many obstacles and good conditions it was probably easy.  At 10 mph they are covering 72 acres/hour.