Sorry, there is no such seeding rule.
It is just 1 & 2 on opposite sides of the draw, 3 & 4 on the opposite sides of the draw. It is completely randomn as to whether the 3rd seed gets the top or second seed.
Lindsay Jelena Maria
Mary : Monica : Svetlana : Sania : Jennifer : Amelie
Roddick : Grosjean : David : Djokovic