C# nearables packet parsing

I am able to parse manufacturer data in my win 10 app. But the confusion is that the packet example for js parsing doesn’t follow for win c#. I can obtain unique identifier as example, from manufacturingdata[1, 8] not 3, 11 as detailed. Have I missed something or is there a different format for parsing with win c#. If so is it possible to understand what that format is or how to find?