They are actually making a difference now though they seem to be going the opposite direction. A comparative test on a starting city with it's first population as a citizen revealed there was an adjustment from the option but it was a little subtle and the Tribe was actually cheaper compared to the non-option game.
I don't think you have much to worry about on the prehistoric game. That's where I actually feel able to stay on top of things actually. Furthermore you're dealing in percentages and not flat rates so it has less impact on smaller values as it is.
I'd keep doing comparitive tests like the above mentioned one I ran to get an idea of how your numbers are panning out.
If you were asking why it didn't seem to be doing anything... the changes are apparently fairly subtle for the system though they may not seem like it. And its possible it wasn't working for you due to some xml load error that wasn't being caught as it would with the debug dll. It SHOULD be fine now. If it continues to seem like drastic changes don't have any effect, then I've got a theory as to what may be happening and how to fix it. So keep me posted.