Having been thru the VA system, which is different than PDES, I suggest you learn the system and handle your claim your self. The saying "Nobody cares about your claim as much as you do" is true. Also the VA system has a "Duty to assist". They have to tell you what they need when they need it. Since this is now the agency you will be dealing with for your disability from now on and your rating can go up as your conditions get worse over time, it is in your best interest to know the process inside and out.
There is another site that Jason and Maparker both comment at called VBN, Veterans Benefit Network, and it is more geared toward the VA.
Yuku | VBN - Message Board
As the PEBFORUM is THE source for the DOD PDES, the VBN has alot of VA related info. I have used a combination of the two and see the experts like I said before (Jason and Maparker) comment on VBN also.
I have used DAV as my service org in the past, however, I now do my own VA work, and recommend you at least know how to do your own even if you have a service org do it so you know if it is being done correctly.
IF I can be of assistance feel free to PM me, however I am a rookie in comparison to others who will be more than willing to give advice.
And if all else fails........do what I do....yell JASON!!! HELP!!!!
Stu