Elward is wrong with his guess, elemental resistance doesn't substract from the damage you get.
The caster level dependent displayed values you get from the "Protection from elements" spell are subtracted from the damage.
The elemental resistances affect the damage you take in combination with the "Luck" stat (it's even a tavern hint in MM3, 4 or 5), they might even work against attack of the specific element exactly like AC against physical attacks.
I don't know where you got your table from, Residue, but I'm sure it's not a table for WoX.
The stats which start the next better value are 3,5,... ,19,21,25,30,35,40,50,75,100,...,225,250.
One raise to the next better con value gives an extra HP per level for example, the rise to 250 (perfect) might even grant the triple bonus (only verified it in MM3).
You see that little stat differences matter a lot in the beginning but nearly nothing later when all stats have been raised above 50.
You can take a look at the very well made shrines for MM3 and WoX at
www.rpgclassics.com, not much was changed from MM3 to WoX.
They copied one manual error however, barbarians are far superior to knights (and any other class) regarding physical combat because they gain extra attacks much faster. Often the barbarian can do considerable damage to monsters the others can't even scratch.