Does flocculated yeast help condition beer?

A recent post ("Cold Crashing Method") was asking about the best method of conditioning a beer. The question essentially comes down to balancing the risk of autolysis with the benefit of exposing beer to yeast that will clean up fermentation by-products.

So this leads to the question of whether yeast that have flocculated to either the top or bottom of the fermenter provide any value in terms of conditioning the beer. Do yeast in the yeast cake continue to provide any conditioning benefit? Do they continue to clean up acetylaldehyde and diacetyl? Or do only yeast in suspension metabolize these residual fermentation by-products?

As a related question, when do professional brewers tend to flush the yeast from their conicals? As soon as the beer reaches its final gravity, or sometime after that? If they flush as soon as FG is obtained, this would suggest that they believe that the yeast cake provides no net benefit to the beer.

Good question. I don't know but I'm posting so I remember to watch the answers. My guess is that only the yeast in suspension will be working to your benefit. Hence the reason people tend to rack beer off the yeast prior to lagering.