black areas in ao map, but normal map looks ok? I'm pretty new to baking maps for game assets, so I need some advice.

My settings are : Cycles, selected to active (with cage).
The normal map seems ok to me, but the ao map has really dark areas that I can't explain.

Am I doing something wrong during baking, or is it my mesh (cubes with bevel) ?
Ambient occlusion focuses darkness on the crevices of the model that's why you have those dark areas. If you didn't already know, the ambient occlusion map is usually used to isolate the edges of a model for wear/tear and (if i remember correctly) it is a linear type of map (black and white image)