No contact shadows (AO) with small objects

since one year I have always problems with contact shadows in conjunction with AO. It seems that the AO has no effect on small objects like chair legs etc. For this reason many objects in my Archviz scenes hover.

Are there some possibilities to tweak the AO to get rid of these problems? (console commands, shader tweaks etc.)

The best thing would be raytraced AO. Element 3D offers this feature and it looks awesome! I hope that this very cool thing find it´s way to the Unreal Engine…

Best regards, Andreas