The original announcement specified that '18 players will participate', but there were 23 different players over the six events. A pair of articles on Chessbase.com -- FIDE Grand Prix: A call for a fair player selection process and Geoffrey Borg replies to Zhdanov on the FIDE Women Grand Prix -- explained how this came about.
I had hoped to document the final Grand Prix standings on that 2011-12 WGP page, but was unable to find them. The official site, grandprix.fide.com, currently lists only the totals through the fifth event, Jermuk 2012. If you're not sure what happens next in the Women's World Championship, see my post on the fifth event, 2011-2012 Women's Grand Prix, Jermuk.