I think having looked deeper, even the FAA appear confused!
I have yet to see, on a TERPS chart (JEPP) any circling minima defined by Approach Category, simply by circling speed which is a far better and easily applied figure. Thus in FAAland, where 5.4.7 states 'must use the approach Category D minimums' for circling it is not necessary, since speeds are the governing factor both under PANSOPS and TERPS, and are tabulated on chart minima for TERPS. The one thing a pilot will readily know is the speed at which he plans to circle, be it iaw SOP or with some particular situation on the day. In Pansops you are 'required' to know and apply the max circling speeds for each approach category.
Apart from the often discussed idea of 'harmonising' circling areas between TERPS and PANSOPS, I do feel it is time for a change, preferably by PANSOPS, to display circling minima based clearly on circling speeds rather than 'approach category'. IE For a 'Cat C approach a/c' (eg 737-700) why not have PANSOPS display minima for '180/205' instead of 'Cat C/Cat D'.
What say the masses? Will it make life simpler?