From the 2014/11/5, mining difficulty almost don't greatly change,
but PBmining "mining income" weekly declines, and the reduction reached to 4~7%
and mining incomes the previous mining weekly earnings with
this
https://alloscomp.com/bitcoin/calculator was equal,
but the recent four weeks there is a significant gap.

Like I said; I think they mine horseshit, dump that and
payout in BTC. Horseshit mining has crashed over the
last couple months both at GAW and Genesis Mining.