I think they refer to that style of belt, A "raised belt". J.H Leather shows a tutorial on a belt & a dog collar of that style. But yes there is a 3rd piece in the center to raise the belt center. I think 2 6-7oz straps would make a super strong belt, especially after a 3 piece is added in the center.
I think the other way they do it is to skive each edge of the belts down. Then that will leave a raised center section, when the 2 belt halves are glued & sewn together it creates the raised center.