It is uncommon if it is a US officer slot.
Having been a personnel specialist in a hospital unit who rose to the lofty rank of SP5 my understanding of the workings of top military command (and even mid-level command) is very,very limited.Add to that the fact that my stellar (LOL) military career ended almost 40 years ago and you've got someone who can't comment with any credibility on such issues.It may be uncommon but might it be,in this case at least,worthwhile?