I think I figured this out....
My P3D v3.3 was installed in my D:\ drive.
When the P3D client did the upgrade, it apparently changed + updated the P3D file located in the C:\ drive and changed the path to open that file. Since none of my addon aircraft were in that file, they weren't recognized. Freakin' weird !!!
So, I moved my addon aircraft over to C:\Lockheed Martin\ P3D, then changed the sim objects .cfg file path and now it's working.
Looks like I'll have to merge the rest of my D:\ P3D files with C:\P3D (Orbx scenery etc.) and then delete the D:\P3D file.
Now I also understand why ORBX Direct was saying that none of my Orbx scenery was loaded. That file was in D:\P3D, not in C:\P3D.
I think I'm going to have a look at X-Plane 11. LOL