AD Navy.
Still going through PEB myself, so take with a grain of salt.
Had some similar things with my addendum. I was diagnosed with Narcolepsy with Cataplexy by a civilian doc via sleep studies (PSG, MSLT), military disagrees but VA DBQ confirms diagnosis.
They do not consider it an unfitting condition, so the addendum basically outlines the conditions I have and is stating they won’t be considered for the PEB.
The only thing that’s being considered in my case is chronic PTSD, which they have diagnosed as unfitting.
You can definitely submit a statement, but if it’s not a condition that will be considered unfitting, it may not help you. That’s just my two cents though.
NARSUM will not affect your VA rating and you’ll likely be rated for that if the DBQ is favorable.
What’s your branch and referred condition?