This one took place on 31 December 1915 but registered on 3rd January 1916 (end column), the other marriage on the page was the same. Why would this happen on a different date please?

There's also a couple of words I'm unclear about, mainly places, perhaps you could give them a go please.
Column one, bottom "According to the ???"
Column four, top, "??? Barracks, Edinburgh"
Column six, top, "Parish Minister ???"