That's my suspection:

The first difficulty in june was about 24% - i think this was the time Bitmaintech has set all available S3 online.
Now the next difficulty was only 3% and they say - hey lets make us the money and say ohhhh sorry we have some problems to deliver our S3 right now.
All S3 are mining for the factory and make money for them - okay they give the customers a little bit discount with an voucher...
And with the next (possible) higher difficulty they deliver - but all money from the 3% diff is gone to Bitmaintech...

Just my two cents...