hmmmm, interesting notation voll, the upgrade proceedure seems to be missing the 100% extra def by conventional thinking, however: http://www.cs.colostate.edu/~deykea/d2armours.html

seems to disagree with what we seem to think, the calculation's seem to be a bit different for eth items or so it seems, other than that im not sure exactly y its like that ?_?

EDIT: bug revealed, after reading the source code of the calculator - "seems*" that its a mis-calculation of adding in the extra 1 into the enhanced def % multipler, hence the def is so low

* - intentional by blizzard? who knows? i dont : /