First thing - don't always believe dealers. You can do this math yourself, or call another dealer and get them to run your VIN, and forward you the specs so you know for sure. Also, I don't think I mentioned it but 2000lbs = 1 ton. A 4500 truck can haul 3 tons and a bit more, but a 3500 has an absolute max of no more than 3 tons. Take 3 tons, or 6000lbs, and subtract the weight of the driver, fuel, weight of the dump bed (say 1000lbs), and any other aftermarket equipment such as pintle hitch, spare tire (generally an option on one tons, so another 75lbs) and usable payload is roughly 2 tons, or slightly less. That would equate to around 5 perhaps 6 yards of mulch with a lower than usual moisture content, or 4 yards with a higher moisture content.