First of all you have a hook fitted much lower and this is the main feature of racing harness. It allows to take a more comfortable position riding any direction and control better gusts.I believe that such a hook's position gives better chances to ride on the leeward edge. The feet pressure might be released easier and more body weight might be distributed through a hook.
Secondly you can lower the racing harness to extreme positions what you cannot do it wit a normal one. In competition I keep it almost below of my hips.
Have you notice that more top riders are coming back to a seat one this year?
Blaszko got a custom made seat harness with low position and crazy ultra light weight. He would not do it without some reasons.
Please try first if you can and spend couple of hours to adopt to the proper position. Then you might take advantage of this low suspended harness.
There is no way for me to try the NP one here...but I will see if I can check a buddys regular seat. My primary reason is my back gets tweaked when I am racing...I think added benefit of the lower leverage. I guess it will put more effort on the legs, but that is fine.