The Nathan Starrs always did have that curious 'cant' to their blades as well. I feel on my canted blade that it started out life as a truly massive horseman's saber, like several canted examples in Nuemann's guide, but was repurposed/clipped and made into a cutlass either during the Rev War or possibly post-1800 for the War of 1812 era. I imagine the cant on a cavalry sword would have helped with the cleaving effect when riding down an enemy. As far as on a cutlass-type blade, it really does aid in the swing, but it is a little cumbersome. Cutlasses weren't made for any 'Errol Flynn' fighting moves!
I remember owning an old 19th c. manual on how to train simple sailors how to fight with them. It was like Step#1- Raise your cutlass! Step#2-Chop the bastard! There were a few defensive blocks and a little footwork, but that was it! A simple heavy killing tool used in tight quarters where there was no fancy footwork and try not to hit your own fellows when swinging!