I know I said I wasnt going to post in this thread anymore, but I found this video and id like you all to take a look at it.
Here, what would apparently be a "world class 3.5 player" is serving 75-ish mph. For the sake of argument, lets assume that he cant serve any faster, and that his serve can only go slower the second time around.
Now, that serve is certainly not "coming". Are you still so sure that most of the 4.0 women you know are serving 25-35 mph less than what you see here on their first serves? I can see a 50 mph second, but a 50 mph FIRST?
I must apparently know only world class players then, because 25 mph less than what is shown in that video as a first serve is definitely slower than any of the 4.0+ girls that I know.
But, im just guessing, and im only measuring with my eyes.