As a Ministerial Servant I went from being the Sound Servant, to the Magazine Servant, to the Literature Servant. I got called into the backroom once by the elders because, as the Literature Servant, I should be placing more books than magazines. I was commended on all other areas of field service.
So, I guess the Sound Servant has to answer the most at the meetings. The Magazine Servant has to place the most magazines. The Accounts Servant has to donate the most money. The Territory Servant has to work the most terroritories.