My DS is in the Waiver Process as well. With regard to my DS, we submitted a bunch of information (overnight) that they received and entered into the system. Two (2) weeks later they requested another doctor visit and more information. We are completing that this week.
I believe the deadline for "being cLeared/waiver approved" for USMMA is 4/16. Which leaves you only a little over a month to get the test done and DoDMerb to review and clear him, so I would suggest you go to whomever you can. Also, review and bring the letter they provided so your physician can review and provide them with EXACTLY what they are looking for.
Good Luck.