I am not familiar with YAC POS calculation. I see this line here
Each chunk of eligible coins has it's interest calculated based on the chunk's age in the range between 30 and 90 days.
Does it mean for POS generation if I have 100 YACs in the wallet for 1000 days I can only expect 100 * 90* 5% / 365 reward if a POS block is found? In PPC POS calculation the probability of finding a POS block is based on coin age capped by 90 days but the reward value itself is not capped. In the above example I would expect 100 * (1000 - 30) * 1% / 365 reward.
I think you are right. I will update the post.
Groko - that is a great post on yacointalk. I've been mining YAC since the launch, and I learned a few things from your overview. Thanks!

And I believe mhps is right - I think YAC caps POS at 90 days. So a 100 YAC transaction at 1000 days would produce the same interest as at 90 days (100 * 90 / 365 * 0.05 YAC = 24.65 coin years * 0.05 YAC => 24 years * 0.05 = 1.20 YAC gained).
Again the guide is very well written, but it maybe helpful to add an example, or two, of how the 5% interest is calculated. Things like the coin-year rounding down to the nearest whole year weren't initiative to me when I originally started. From the example above, I would have expected 1.23 YAC instead of 1.20 - it boggled my mind why all POS were 'rounded' to the lowest 0.05. I figure if we can save someone an hour of sifting through the forums, it will benefit the community.
