So far the only differences i can see is that you open with Kassatsu (ewww lol) and that you substitute a Raiton for a shorter GCD Shiruken. I'm not sure why the Shiruken was used can anyone break this down for me?

I know that Shiruken is best used in situations where you wont have enough time to refresh Suiton (Sub 20 seconds) if you perform a Raiton. But it doesnt seem to be the situation in the video.