If the wc claim is about RSD then he can only apply his exam to RSD. It comes down to what the wc claim is about , unless the others things are something added to the claim, or before the claim and co factors in the RSD...

They make it so technical...

LOL many IMEs are wacked

Just remember they are paid by the wc ins company...so they usually aren't looking to help you.
Unless they happen to have very high scruples and really care about helping people, but those are few and far between.