I consistently notice Yung-Jan Chang in 2nd weeks of Slams in single, and in one of my games, Mattek Sands is #4 in singles at the age of 33 having won Indian Wells, Tokyo & Rome, been in the final of Miami & Beijng, semi-final of Wimbledon and the WTA Finals, all in Singles

Both these players have SingleDouble=0.9 and if my understanding is correct, their RankPerYear should reflect the Doubles ranking rather than the Singles
Mattek Sands' is RankPerYear = 524, 533, 106, 107, 120, 46, 36, 27, 17, 17, 17, 17, 48, 110, 3, 1, 8
and BestRank=1