Derek, my example must be extreme. Only then light might fall to the
obscure points.
My current interpretation to that strange behavior: it is part of a
piece's value, that it is able to risk its own existence by entering
attacked squares. But that implies that it could be covered by a minor
piece. And covering is possible only, if there is at least one enemy piece
of equal or higher value to enable a tolerable exchange. In your and mine
examples that is definitely not the case.
My conclusion is, that the most valued pieces will decrease in their
values, if no such potential acceptable exchange pieces exist. My
assumption to that is, a suggested replace value would be:
( big own piece value + big enemy piece value + 1 pawn unit ) / 2
This has to be applied to all those unbalanced big pieces. ( Just an idea
of mine ... )
P.S.: after rethinking on the question of the value of such handicaped
big pieces (having no equal or bigger counterpart) I now propose:
( big own piece value + 2 * big enemy piece value ) / 3
