I don't know about FF except my father-in-law only has 26 matches all 5th cousin on FTDNA which is too high for the 1 in six thousand level for 5th cousins.  It is true my wife and I have about 1 page (25) 4th cousin projections on 23 each which does strike me as overly optimistic.  But the # of projected 5th -7th cousins on 23 is about right.  People on average have about 256^2-4 cousins of level 7th or closer which is about the ratio we find at 23.  And if we allow for culture which implies being genealogically interested means having genealogically interested relatives (e.g. Ashkenazi and Mormons), the ratio is even better.