assumptions are made in the simplifications. You have to know and understand those assumptions before you can properly apply simplified equations. I don't mean to be inflammatory, but if you pursue more advanced classes you will see the convergence of "equations" and reality once you aren't being pampered with over-simplified math any more.

I don't have anything in 5160 so I might grab a custom someday. They really don't excite me that much though(why I'd rather have a custom).