I don't know if this changed, but I got mine today from talking to Kuldu. I didn't have to do the Merchant's Union quest for it. I was on the Desire for Better Weapons quest and happened to need to talk to this guy for it. Not sure if the quest was a pre-requisite, but I got the knowledge from him with 5 energy, no problem.
I have finished both side and I still cannot have this knowledge so I don't know what is the issue here. Now I'm doing again maybe I missed something but I doubt it.
For this knowledge you need to complete the Mediah Main Story quest line, but you need to pick the correct cross roads. When you get the choice for a cross roads in Mediah you need to take the crossroad on the left, the one for Sarma Anin. If you pick the one on the right for Neruda Shen you will not be able to get this. Once you complete the story for Mediah you need to go talk to Kuldu who will have the knowledge, he is the Luxury Vendor for Altinova.