Advertised mileage vs real mileage

[Solemus]

I am flying out of Leeds UK and noticed that there were a lot of routes with less than 20 pax, so I thought I'd take a chance on the Fairchild SA227-DC Metro 23 which is a 19 seater. I am wondering why an aircraft advertising that it can do 1190nm will only do less than 600nm without a warning message coming up about pax not wanting to use that particular aircraft because it is a small aircraft. I know it's about weight and stuff, but, why advertise something when it's untrue?

[Sami]

Metro 23 has a range of 1190nm with the full passenger load. Any payload limitations on routes shorter than this are caused by the runway performance then, and not by the range performance.