McCormack DNA-1 Rev A question

I was fortunate enough to have purchased a DNA-1 Dlx Rev A from a fellow Audiogoner. The amp that it replaced is a DNA-1 Deluxe. Yes, I am moving up the food chain, and boy does it taste good. The question I have is what is the purpose of having 2 sets of Cardas binding posts for right and left channel? I know this is a 2 channel amp. I just connected my speaker wires to the bottom set of posts. My original Deluxe only has 1 set of Cardas binding posts on the bottom and it looks like there are some screw type of binding post above that. I couldnt figure this out so I had to ask. Thanks for your responses
The second set of binding posts is for shotgun biwiring, if your speakers have separate posts and IF you want to go that route. 1 set of speaker cables to the woofer posts and a second set to the tweet/mid posts.
When I owned a McCormack DNA-1 Deluxe or standard I used the top screw type binding posts when I had spade terminated speaker cables. The Zu Audio WAX spades were a little larger than the norm and when I used the top screw posts on the DNA-1 they securely held the spade there and there was a lot of surface area for the spades vs the binding posts. I was definitely sure there would be contact. In my experience the either post worked fine. It is just a matter of preference.
Exactly right - thanks, Swampwalker.

Best regards,

Steve McCormack
SMc Audio
Swampwalker, just for clarification; I thought "shotgun biwiring" is when there is one + and one - on one end of a channel of speaker cable and two + and two - on the other end of the same channel of speaker cable. I thought what you described is typical biwiring, either with seperate dual individual runs of speakers cables for each channel with one + and one - at both ends of each dual run, or combined/connected runs of speaker cable with two + and two - for each channel at both ends.
Unsound- I guess we all have different ideas of the semantics involved. If you go thru the various threads on this, you will see lots of confusion and if I contributed to it, I apologize. One way to perhaps differentiate is to call them internal or external bi-wiring. Internal, in my mind, is a single + & - at the amp end and separate + & - at the speaker end, one set for the woofer and one set for the mid/tweeter. External bi-wiring is two completely separate runs from the amp. Now they can be on the same amp binding posts, but that can be ergonomically difficult. Or each of the two separate sets of cables for each channel can originate from a separate set of binding posts which is easier to implement for the consumer and less likely to result in shorting across the amp's binding posts.
Swampwalker, I guess your right re: different ideas of the semantics involved. My idea of internal bi-wiring is the appearance of one cable with 2 + and 2 - on both ends for each channel, and external bi-wiring is two separate runs with 1 + and 1 - at both of ends of both separate runs for each channel. And shotgun would be 2 barrels from one trigger. :-)
Unsound- WRT the OP's question, regardless of our own interpretation of the semantics the answer about the 2 binding posts is to facilitate bi-wiring. More importantly, it is NOT to drive to sets of stereo speakers.
I am learning something new all the time in this hobby. I didn't think of biwiring since I've been using Jumpers all along. Thanks for everyone's responses.
If you are considering bi-wiring, and for what ever reasons, some speakers seem to appreciate it more than others, I'd suggest using 2 separate runs for each channel.