c cast photons though this is normally refeered to as cast rays g gather photons this is normally referred to as gather rays
the two are linked to lighting conditions
could be something they have done to quantify whats going on with photoworks when using the the mental images part of the renderer
its called emiot photons and final gather in the fully blown mental ray renderer ive seen this before when using mr standalone
dont qoute me though its probably normal and i doubt you will find any contol on the photon emission or the gather as they have probably linked the two within certain boundaries to give you a good lighting result instead of getting it horribly wrong and over or under exposing the scene
this is all to easily done in mental ray if you dont quite understand whats going on so my guess is theyve nade it idiot proof in photoworks and taken the controls out to some degree