Hi MC, 

What you are asking about is Multi-pass Rendering. Photoshop Elements can sort of handle the various layers but what it can't do is handle different output channels – only the full version of PS will do that. 

In brief, the various layers and channels can be used to make selections or be blended with existing layers to enhance or modify lighting - even relighting a scene after it is rendered. It's a really cool ability. Everything can be changed in post including abmient occlusion, the color of the light and so much more.