I can see two possible meanings to their statement: 1) They adjusted the amount that temper scaled with enhancing magic skill (possibly in a downward fashion) or 2) They removed the cap at 500 enhancing magic skill, thus allowing the spell to scale higher then previously (seems more likely since they already did this with En-spell damage).

Or it could possibly be both, i.e. the upper limit remains the same but can now only be reached at a much higher enhancing magic skill number.