Variation for A, B and C class units

Question: when would I want to introduce different classes of units?

Answer: you may have different levels of unitholding. For example, there may be the "owners" who would want to participate in both income and capital appreciation. Then you may have another level of "investors" who may only want to receive capital appreciation. By the same token, there may be employees that you would want to reward and give them access to a share in the profits only. They would be another class of unit holder.