My DS called DoDMERB and told them that he was an AF dependent, it was immediately changed to our on base doc. DoDMERB just looks at your zip code and goes from there to the closest doc, they have no clue that your DS is a military brat with access to the military docs.
I disagree with others, take it on base, those docs know what the military is looking for medical clearance compared to the bizarre urgent care that was contracted for maybe just your kid and does it once a year. Additionally as a military dependent that doc has access to their medical records from birth. Many times a kid will check a box that may require a remedial. The bizarre urgent care doc is going to take it at face value, the military doc will look at the records and determine from that point. That could be good or bad, but it helps when the doctor knows the exact requirements for whatever the issue is.