Actually there was another scientist who thought timing swayed as well, but unfortunately his data seemed to indicate that timing around O was GIRL timing and cutoff = boys!!! Exact opposite of Shettles timing.
Something else to consider is a big part of Shettles is the abstinence for swaying pink and then the 2-4 days BD pattern for blue...plus the positions. He also used to include douching in his advice. This is most likely what was doing the swaying (if anything.) and timing is just coincidental to the rest of it.