Do we know if the customers definitely pay the fees in full? One might imagine a large customer (like a pension fund) might be able to negotiate a discount, and the discount might not show up in the published returns, or something like that?
Even in the old days, 2 and 20 was the starting point for a negotiation. If a client can bump up a firm's assets under management significantly, they have a lot of bargaining power.
It's unusual to pay the sticker price.