It's strange that the level is so much higher. Something is going on. Just a thought, is your sound pressure meter pointed directly at your center speaker? I don't know that this would make a huge difference but it's something to consider. I point mine straight up when calibrating my system.
Aperion Verus Grand Towers & Bookshelves, Verus Forte Center, Infinity Surrounds, Ultra-X12
Oppo BDP-203, XBOX360, Xbox One
LG 65" OLED
RR2150 w/Klipsch SCR-2