Okay, so did you actually measure the head thickness and compare against stock? Since you've already checked for a wedged shape and found that within .002 (close enough I'd think) then now you just check to see if it is a combination of deck height and valve installed height.
BTW, your explanation of installed height causing the lash adjuster to pump up higher makes good sense. I'm comfortable with that answer.
It also fits my logic that it could have been an increase in the pivot point height..
