Lower --aq-strength in --tune grain

[martinfrombern]

I've been looking at which adjustments --tune grain does, and all of them seem pretty logical except aq-strength. I'd like to know what's the logical explanation to use aq-strength equal to 0.5 (half the default) when preserving grain? From what I know, aq takes bits from the edges and puts them on the background, so it seems to me that aq should be very helpful in preserving grain there.
Additionaly, why it isn't good idea to use lower ip/pb ratio on all sources?

[Dark Shikari]

The purpose of --tune grain is (for high bitrate encodes) to deliver a more uniform level of quality across the video and frame. Lower ipratio and pbratio and higher qcomp accomplish this across many frames, and lower AQ accomplishes this across individual frames.

[martinfrombern]

and lower AQ accomplishes this across individual frames.so, if i undestood you correctly, using default aq-strength would mean putting too many bits into keeping background (flat areas) noisy/grainy?

[Dark Shikari]

so, if i undestood you correctly, using default aq-strength would mean putting too many bits into keeping background (flat areas) noisy/grainy?Moreso the problem is that too high a quantizer on edges and complex areas may stop the grain there from being retained.

[dvy]

I want know setting aq-strength = 0.5 which can lose human face detail or make human face blocking?