Nanopool on Twitter: "SIA pool commission changed to 0%!"
and a reply from their staf:
"The thing is:
Due to SIA ASIC launching - SIA difficulty is quite high now, therefore many less blocks could be found.
Please check this link out: https://siastats.info/mining.html "
I do not know anything about how the DAA is implemented, but I am sure that the DAA is using an average method over the last x hours|days to calculate the new difficulty. The difficulty should, but mustn't, depend an the hashpower. The hashrate is reported by the mining pools and possible is wrong.
The big problem is related to checkout threshold: it has to drop proportionally with mining difficulty. Up to now we have an exponential increase in difficulty and only a /5 checkout threshold. It's becoming impossible to receive already earned coin