Well I guess I am the exception to the rule. I have 14 hens and had 2 roo's that were raised together. One BO and one SLW, all was fine and the BO was the boss and SLW always ran away from BO. They did knock each other off of the hens and such and a few "favorite" hens were getting over used. Roosters were about 10 months old and from one day all is fine to the next saw roosters sparing, puffed up necks and all. They fought all day, I left them alone thinking they would work it out well the BO ended up giving in to the SLW and BO was ousted. I found him on the other side of the barn by himself a bit beat up and looking defeated, SLW was in the coop with the hens and they never could live together again. I ended up finding a home for SLW as he was "more colorful" so easier to find him a home.
I want to bad to have a beautifully colored EE or a full Ameraucana to replace my BO but my BO is such a even tempered boy and never wants to even think about challenging me so hard to think about letting him go.
I don't think you are the exception to the rule. Often roosters can work out a good partnership in taking care of the flock, but sometimes they cannot. Sometimes certain hens cannot get along and live together. They are living animals and anything can happen.
It is really nice when roosters can get along, but roosters can cause problems. My normal advice is to keep as few roosters as you can and still meet your goals.