I think it is perfect. Armour +5 (vs. all) is conditional. E.g.
AL+5 (while health is above 50)
and...
Al+10 (while health is below 50, or while hexed, vs. slashing, blunt, cold etc.) - greater bonus in highly specific circumstances.
AL +5 (vs. all elements)
AL +5 (vs. physical)
Doubt it'll hit 650k, but you may as well put it on High End and see what happens... Worst comes to worst, if you don't want to sell it, the highest bid may be close to its actual market value =-)