Oh, and Social Security doesn't consider me disabled, but that isn't news since I knew they would rule that way simply by looking at their criteria. But to apply for my IRS disability retirement I had to apply for SSA, because if one is granted SSA benefits, the IRS reduces the retirement payments by that amount. I was never in any doubt about what would result - as SSA says in their assessment, I am disabled but not completely unable to work. The fortunate and differentiating thing is: to retire on disability from IRS, the standard is rather being unable to work at any position available to be offered me.
On the latter decision, I am still waiting to hear.