Having risen to the lofty rank of SP5 (E-5) during my stellar Army career I'm unfamiliar with those in the stratosphere.;-)
Army-wise,a Master Sergent (three up,three down) is an E-8.Then the various Sergents Major,I assume,would be E-9 so I assumed (or suspected) that the top Enlisted Man in the services would be E-10's.
I was wrong.
I also rose to the lofty rank of SP5 during my short Army career.
I was designated a Personnel Management Specialist, so they filled my military mind with such matters.
Since our time, they have done away entirely with Specialist ranks from E5 to E9, with only SP4 remaining.
Thanks for your service.