I'm a bit skeptical, what does "a day" constitute?
Did MF actually run the spreader for a day, or take the time taken to spread one full load and worked it out from there?
The wording could mean that the spreader has the capacity to physically spread that much in a day assuming it was constantly topped up, it does not have to mention loading or travelling which is an unknown given you could have a chain gang on pitch forks and a 5 mile trip to your muck
On the behalf of FTF, I will get onto the ASA first thing monday and get this "mess" sorted out!