Hello all! First time poster, long time reader. Anyway, I just bought a JBL GTQ400 amp. Unfortunetly, I didn't look at the amp close enough before I started running my power wire. After running my wires, I noticed that the amp has two power connections!!

I am by far not an expert, but I have installed a few amps, and have never seen a requirement for two power connections. Is it a necessity to use both power connections, and if so, why does it have two instead of just one?
My second question is, can I use my Fluke multi-meter to measure how much power the amp is sending to my sub? I am using this amp to run my 4 ohm Kicker CVR-10. This sub has two voice coils, so I bridged the amp to power each coil. I just want to make sure that I am sending (as close as possible) the same amount of power to each coil.
I appreciate any help thatb I can get. Thanks for your time!