Here, you can see that moss and buildup on the low slope portion under the deck. It would be suggested to replace this portion of the roof with a commercial membrane or coating. The asphalt in this section appears to have some minor leaks.  Service to this area will likely require removal of a portion if not all of the deck.  

Here, you can see the water has infiltrated the roof beneath the deck. It is unclear if these are old stains or new, but likely active upon inspecting the roofing underneath.

In this photo, you can see that a tar-like substance has been applied to this small section of Flat Roof. This is an acceptable solution but may need to be coated again in the near future.