Hi Bill, the way i used to use an ambient occlusion render was to get a better idea of where the hot spots were and for seeing the depth to the shadows, allowing you to adjust the lighting to better suit the final render. Since there is no AO in KeyShot, the way it was used here was to assign everything other than the glazing in the window with the Occlusion material type, changed the CMYK to 1,1,1,97 and let it render for Max Time for one hour. The images were then combined using layers with Multiply, and then the brightness and contrast were adjusted to get some more depth to shadows and overall tone to the image.
If you look at the carpet, it's a little darker in shade, as is the duvet cover, and look into the far corner and you can see the shadow gradually getting darker as it goes down the wall. It's subtle, but noticeable. I could make it darker if you want.
Here's the occlusion render should you want to play with it for yourself. It's the same resolution and same render time as the main image.
Martin