For the financial split, the goal is to come out with something viewed as fair and reasonable. However for decision making, it is critical to have some way the company can make effective decision. If, for example, the co founders are on a sailing ship suddenly see rocks dead ahead, a decision must be made whether to go to the right or the left. The worst thing is not to be able to decide because two co-founders/co-captains have equal shares/voting and there is no mechanism to effect the decision.

Further more, if two (or more) co founders cannot decide before hand on how to deal with a deadlock, then it is always better to quit while you are ahead.

And yes, I had this experience as well as one that was the opposite.