Brian, in an earlier post I corrected your statement that Hogan's leg is straight at the top of his backswing. I said "trust me, it isn't".
In this second analysis you refer, to me presumedly, that I am in my own world for thinking it is not straight.
In an earlier post I also cautioned readers about flawed analyses, going so far to imply this is a central problem with golf instruction.
One day you will get some good video of Hogan from down the line and you will discover "you should have trusted me".
While Hogan usually wore blocky pants that tended to hide his rt. knee flex, there is little doubt the right leg/knee is indeed flexed.
The interested reader need not take my word on the matter. It is self apparent in footage from "In Pursuit Of Perfection" or the Shell Match.
Anyway, this is how things go wrong...and the innocent student suffers.