Thanks for the info!
I sort of figured it out though, just haven't decided if it's a better option or not. Under options, File readers, DWG, there is a toggle to "merge 3D faces". Navis was taking all his ductwork and merging it into one surface. Now with that option not checked, each individual 3D face will clash with each. So, It's either over simplified by not seeing the immediate area or amplified by each individual 3D face... For instance if there is a clash near a supply grill, there are 20+ clashes because of all the individual 3D faces that are used to create the grill assembly.
Pieter