That's not true, BtS great artists provide a flat culture bonus that is the same throughout all eras. K-Mod for example introduced this rule. Also, your post is contradictory. Does or doesn't the change to 800 work?
Ok, here is what I have:
#1: Screenshot of vanilla BTS; with greatworkculture of 1,000
#2: Screenshot of KMod, which MMod is built upon, with greatworkculture of 800.
To answer your question regarding contradictory; yes, the 800 change works in KMod. With each advance of era, the great work is multiplied. So, it goes 800 > 1600 > 2400, etc. What I am trying to do is reduce this (or, even better, simply disable the great work culture bomb). If I reduce values from screenshots [vanilla] and [kmod] to '0' ... the game remains unchanged in that the culture bomb is remains in effect. So, changing the culture bomb to '0' in both vanilla and kmod aren't doing any in-game changes ... and I don't see any other value to XML line to change or modify to enact this change? Any suggestions regarding this? If the XML is being ignored for some reason and no changes to these will help, is there another suggestion, up to and including disabling great artists? If so, what value has to be changed to disable them?
Note: If I change vanilla value to 0, and play a vanilla game, the culture bomb disappears. So, somehow the XML is being ignored for the culture bomb value in KMod. So, I would have to find the source of this I assume, or disable the unit?
Note: Besides the culturework change from 1,000 to 800, I've uploaded screenshots of the only other line changes [screenshot vanilla2 and kmod2]