Good luck with the 705 Ian. You'll enjoy it. You have a back light on it too, just for those times at night when you want to go out to play!
The strange numbers you are seeing on iron, are probably what is called wrap around. Think of your discrimination numbers as going in a circle and not a strait line. Iron can read as iron, but also come in on some of the high numbers as well. If you knock out the highest notch, it should help reduce this from occurring.
Good luck with your wife's cancer treatment. Not a fun thing to deal with, but it's beatable. a lady I work with and my mother in law have had a number of bouts with it and won.
Mick Evans.