Those CFL's look like they maybe be blocking the HPS from lighting your plants in full. Also you could just use the CFL's to grow then switch to the HPS for flowering.
Depending on how many watts for your HPS is how much light heat will hit your herbs - also the space too. I figure if you have a 200 watt lamp then you would want it 8 - 12 inches above your tops depending on circulation but that is a guess estimate. Testing your limits could cause burning or loss of light though.