I got in so much trouble in 1993 when I told a female E-7 that the only way she got selected is due to the difference in PT scores. If she had been judged equally with the men, she wouldn’t have made E-6, much less E-7.
Even in my day (75-86), some of the most unfit (fat) sailors were E-7 - Chief Petty Officers. I never understood why the commands let them slide. Below had regular fitness tests/requirements. Many of the Chiefs couldn't even touch their toes if they had a rino on their back.
Still, I wanted to make Chief until I got a great civilian offer and discharged at E-6. I can't remember the equivalent of Army or Marine E-7(Sergent Major?), but Chiefs pretty much ran the sub boats and smaller surface ships. They had their own berthing quarters, mess, and free gangway privileges, not to mention no more ugly cracker jack uniforms.