I think you are fortunate to have had a doctor willing to work with you towards the goal of disability. I've heard so many stories about doctors less enthusiastic.

If it makes you feel better, my doctor also wrote a letter adding 'schizoaffective' to my bipolar diagnosis. I cried. But he explained to me not to take it to heart, that while I was borderline that condition, it was necessary to paint the darkest side possible to my illness in my application for a medication exception designation (in order to get Abilify which is not a covered drug here).