Not to step into your army-navy thing with Pusser, but that's not always true either... when I was a Pte clerk in an infantry regiment, fully qualified to Cpl and with more than enough TIR, no promotion appeared for several months... meanwhile my infanteer buddies with the same TIR & quals were getting promoted with much fanfare on the armoury floor. Finally I asked my CoC about it, and the reaction was like "oh - that's right, we hadn't thought about the clerks." My promotion finally did come a few weeks later, with no back-dating, & was handed to me in the OR by the DCO with two other clerks in attendance, long after the rest of the regt had left for the day.
This was over 20 years ago; hopefully things aren't done that way anymore. I never forgot it, though, and not in a good way. On the bright side, as a good lesson in what not to do, hopefully some of my own troops benefited from it over the years.