I've personally run a 14.1 league in the past (as well as participated in it before I took it over) and can tell you from experience that some matches will go well beyond 2 hours. But not all of them will. It varies greatly on the level of the two players playing.
Sometimes it can just be a drag down, knock out safety fest... in which case some of our longest matches were 3 to 3 1/2 hours. And this did happen every week of the league. There was always one or two matches that took this long. On the flip end of this though, are the majority of players who get through a 100 point match in a shorter amount of time. But I would say the average is about 2 1/2 hours from what I saw in my experience.
One more note... the 14.1 league in which I participated and operated was a handicapped league (that changed every week based on whether you won or lost). If every person in your league is racing to 100 regardless of playing level, some matches will be long and some will be short. Just depends. 2 hours for the whole league to be finished is not very likely based on my experience, IMHO.
Hope this helps.
Ray