He is running 7.1, the surround "BACK" channels are being powered by the receiver and the "SURROUNDS" are powered by the Emotiva, so all channels on the amplifier are being used.
Zephaholic, I would redo your settings or maybe just adjust the surround back levels, as they may be off a tad (the output level might be too low or too high). The subwoofer might also need to be leveled up or down.