Some would say that ratings are subjective. What makes the difference between one rating and another, a single line or word at times or a single frame?
For "Jaws 2", it came down to bodycount. Billy Van Zandt (TMP's Rhaandarite bridge ensign) had to film two endings for his character: eaten by the shark and
safely reaching the rocks. His was the crucial death that would have tipped the movie into an "R" rating, box office suicide for the teen date movie it was created to be.