Yes, same thread or different thread, would make no difference to me. I am working on Ch. 4, as I said, but in a _very_ relaxed way.
It has occured to me that Waldek should post the FriCAS results for the two cases he could not verify by differentiation. Perhaps they are correct, perhaps not. I doubt that results with mixed branches should be counted as successes: numerical evaluation would fail even on FriCAS, I suppose.