What happens at times is that a given Master may "tinker" with some "minor points", such as how much ( or how little) movement is done by the legs.
Some IW forms basically stay in the same place while others move forward.
This could be because the Master may not have had enough "room" in his class OR perhaps He thought it was a good idea to shorten the distance so that the student could do it "anywhere".
Sometimes the sequences are different and again, that may be because a given master may have personally preferred that and passed it on to his students.
It is the principles behind that form that matter, not so much the sequence and so forth.
Psalms 144:1
Praise be my Lord my Rock,
He trains my hands for war, my fingers for battle !