"Old Age" system in Dom3 - need some info

[Wick]

I just checked it out and each point of nature magic adds half of your baseOld to your Old. A elegant way to test this is to pick a pretender with nature and look at it on the next screen (that lists magic, dominion, awaking...).

Each point of Fire subtracts 5 from Old if Old => 200 and subtracts 2 if Old = 50. The only test case I found 50>x>200 was the Golden Naga (334) whose f2 gave her 69. I didn't check the <50 case.