I could be wrong, but it seems that the two related stats, DiplomaticTradeOfferValueMult and DiplomaticTradeOfferValueMultMinors don't have any effect on the game. This makes techs from many factions (e.g., Passionate Communicator specialization for Terrans) as well as the Feared ideology trait (second option in the Malevolent Awe branch) worthless.

I played with these in the xml, and even at much greater values, they seem to do nothing...

But perhaps I'm misunderstanding something--in the Terran tech's description, it says, "By clearly communicating our thinking to outside parties, they may begin seeing the same way as us, boosting whatever effects we hoped our ideology might cause."

Is this linked to ideology? If it is, it may be working as designed. But it doesn't seem to be doing anything, so I'm not convinced it's working at all...