Hey

 

so since i have lvled this part before i dissmissed Vette before talking too the quest guy because i diden't wanna get minus, but for some reason i still got minus affection in the end, so my question is,

 

How could i get minus affection with someone who wasen't even present when i pressed the choice?

You need to summon a different companion, not just dismiss her. The game still considers her to be your active companion even if she isn't standing next to you. The ship droid is great for this since he doesn't care what you say or do.

Sometimes it does the affection modifiers for every companion who was active for the mission (and you never know before you finish it), and sometimes you get affection modified even if that comp was never active (usually for class missions ant the end of the planet (but not always)). But usually the summoning of another companion works.