Ambient Occlusion (AO) with GPU Lightmass

Hi, im baking my lights for VR with GPU lightmass, everything looks good but the AO could use a little boosting. I dont want to add the AO through the Post process, as it kills my VR performance, so is there a way to control the static lighting influence of the AO? I basically need heavier AO with GPU light mass if anybody knows?