Joseph,
It isn’t materially different than your rephrase. I had only read the first page of the thread when I posted that.
As to you second question, I have two reasons:
1) It is not clear to me that CS is muttar. Rav Moshe’s heter was a chiddush, not universally accepted, and Rav Moshe himself felt that if a person was capable he should be machmir.
2) Even if klapei shmaya it is mutar, if you are machmir because you think that there is a solid argument to be machmir then the self-control of your tayva will benefit your soul and you should get “schar halicha.”