Rules at horse pulling contests are different in different parts of the world.
The Midwest uses the distance of 27'06" for a qualified load, while other places may use 15 feet or 12 feet.
Some places may use 3 pulls on a load , where you don't add up the pulls. You must pull the full distance in one of these three pulls to get on another load. There's places where you pull within a time limit. You just keep pulling a weighted load for a certain time frame and they add up all the distances that you pulled within the time limit.
Some places make the horses wear blinds on their bridle and some places don't care if they are blinded or not.
Some pulls have weight classes per team. If a team weighs 3200# or under, they are in the 3200# class, etc. Overweight pulls are determined by what the team weighs and they pull a weighted load determined by each teams weight.
So you see, there are different ways to have a horse pulling competition and it usually is determined by a group or association that these teamsters belong to in their area.
That doesn't mean that you have to stay and pull a certain way in your area. Many teamsters travel good distances to pull a different way with different competition. The Michigan Great Lakes International, itself, has drawn 35 teams per class from several states. Muhlenberg pull, in June, once had 55 teams from all over the place.
The major factor in drawing teams from other places is the prize money in which is paid out. The higher prize money and more places that are paid, the more teams can be drawn if it does not interfere with another big pull.
Associations have annual banquets that members can make and change rules at. Thus, is a group decision.