Please remember that the % in our statistics is actually the percentage of people who were able to get pregnant doing these things. Many people were not able to and that is not represented in the data but it is something that is always first and foremost in my mind.
If 100 people start off doing a super strict sway tactic and only 10 of them get pregnant, and of those ten 7 get girls, that is 70% success rate but 90% did not get pregnant using that tactic and thus it was utterly useless to them. (and of course also the issues with taking too long to get pregnant, etc mentioned in the post above)
If 100 people start off doing a sustainable sway tactic and they all get pregnant but only 65% get girls, that's 65% and yes, lower % than the above super strict tactic but WAY more people walk away from the table with a baby girl that way.