In all honesty, it was developed fairly late in the process, and I didn’t really have the time I would’ve liked to iterate on it and refine it (which is why the medals and awards stuff didn’t appear until the Command book). Similar with milestones for advancement - If I could screw with the timeline and rework them with the benefits of hindsight, there’d probably be some notable differences.
As the shows tell us, senior staff say in the same roles for years, if not decades. By the end of the TOS movies, the main cast were all Captains and Commanders - Kirk having become an Admiral and then come back down to being a Captain - and only Sulu seems to have left the Enterprise for good (Scotty and Chekov get assigned to other ships but come back later). For the TNG cast, by the time of Nemesis, Riker is only just getting a promotion to Captain (he’d refused promotion since season 3 of TNG), and only Worf had actually had any real career progression (achieved by moving to a different show). There are a few more promotions in DS9 (everyone with a rank in the main cast gets promoted at least once, except Worf who gets a political career instead), but nobody gets promoted up and out (Sisko nearly does, twice, though). And there are only two officers who change rank in all seven years of Voyager (Tuvok and Paris).
Besides, as Kirk says to Picard in Generations:
“Don’t let them promote you. Don’t let them transfer you. Don’t let them do anything that takes you off the bridge of that ship, because while you’re there… you can make a difference.”