This is a really interesting thread that has diversified somewhat. Having spoken to both Pauls I tend to think that they have identified their markets well and work within what is most effective for them. Neither can compete on economies of scale against bigger players, but they have found what works for them and have built brand loyalty around it.
As regards top end clefts, my take on it is that relative scarcity across a number of categories may be a factor in some clefts realising a higher rating. Most of these scarcity factors, in my opinion, will be aesthetic. For example, clefts with high numbers of very straight, even grains are scarce, likewise ultra light clefts which will make a bigger bat for the weight, and also very clean, white faces. Obviously some clefts may possess one of the aforementioned qualities, but very few will have all three, therefore the ones that do will generate a premium price.