DFAO is highly contrasted and unstable

I am pretty new to DFAO, and am finding it impossible to get soft falloff with AO. A get a super contrasty AO in concave sections, and nothing else. The AO dances around a bit too.

I tried lowering the contrast, and it really makes little difference. Project is under NDA, so I cannot share images.

What am I doing wrong folks?

Thanks!