Dave,
I recall reading a paper written some years ago by the RAF at Bedford regarding the BERP and trailing edge swept down technique. The results if memory serves were pretty conclusive regarding control loading, and do seem to be borne out by in service operations, at least on EH101. Basically during the trial, various abrasives were attached to the outer 25% on the blade leading edge, everything from course sand to sea salt etc. The results showed that the finer the abrasive, the more pronounced the effect. The effect was that with abrasive build up, e.g. flying over the sea, the effect on the blade tip increased load on the pitch control mechanism to the extent that in some cases, the pitch control rods were at maximum stress loading at only 40% of aircraft max forward speed. This resulted in the aircraft chewing pitch change rod bearings like you can't believe.
Anyway, not sure if this helps.. food for thought hopefully.
GW