I hope some of you more experienced teamsters can help me with a question. I bought this three horse evener from a neighbor four or five years ago but have never used it. Recently I was looking it over and discovered that the three singletrees are not the same length. The left and center ones are 31" while the right one is 24.5". Is there a reason for that? It doesn't appear to have been modified so I'm sure it came from the factory that way. Any ideas?