I didn't say that the Force Attenuation of the options are what affect Corso's affection. On this mission Corso's affection gain or loss has to do with you actions regarding the Empire not whether or not your choice was light side or dark side.
You lose affection by selecting the lightside option not because it is light side but because your action promotes collaboration with the empire,
Choosing to expose the senator causes gain because your action opposes collaboration with the empire.
For a person playing a Smuggler with a moral compass and That cares about their standing with Corso it is a catch 22, you have to either accept dark side Force Attenuation points, or accept a loss of affection with Corso.
The choice may have absolutely no bearing on any other class' companions, i was speaking Strictly about my specific class and companion.