Key 1 2 3

      4 5

1. Percent Allegiance with change rate

2. A culture hub on planet at base rate [6.7 each]

3. The same culture hub with 10% increased culture rate researched [6.7 each]

4. Another hub added at 10% increased rate researched [7 each] (updates the old one to the correct rate)

5. both the old hubs scuttled and a new one built at 10% increased rate [7 each]

I ran a few tests and if a culture hub has a base of 10 a 5% increase makes it 10.3 (persuably rouned up from 10.25) and a 10% increase makes it 10.5

Notes:

    All tests done with advent. 

    First test temple of communion had base rate of 6.7, all other tests I did had a base rate of 10.

    I am unsure if the tool-tip is incorrectly showing the culture rate or if it doesn't update the rate when you research culture tech

    Tested on Diplomacy 1.31.

That's okay I think I misread. A bit late for me. >.<

One way to check to see if the tooltip simply isn't updating the numbers or if the research doesn't take effect until a new structure is built is to use dev.exe to have 2 players build culture structures on adjacent planets, watch for the point of equilibrium between the two cultures, and see if that point changes after the culture upgrade is researched (for only one of the players, obviously). However, I strongly suspect that the the true numbers simply aren't updated properly on the tooltip.

I'm lazy, though, and don't want to have to reset all my settings by using dev.exe so someone else'll have to do it if we want to find out what the problem is.

Yup, that -0.07 rate is defined in the gameplay.constants file. I've always said if the devs or a mod wanted to make culture more worthwhile this number should be increased, but I don't think anyone has bothered.

Only if its allegiance starts at 100%!

Also, I've noticed that sometimes you can get changes of up to something like .1/sec (in the positive direction) under certain rare circumstances. I'm not on a computer with access to Sins at the moment but I'm wondering if it might be possible to get large negative allegiance change (larger than -0.07) if the planet is completely overwhelmed by enemy culture and is at an allegiance level higher than the maximum allowed (due to the loss of a homeworld or Advent starbase).

Then again, if the -0.07 is something specifically coded in...