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...
Bitmain stated in an earlier post that they only had an S2 farm and 1 S3 for testing. They could be lying who knows. The recent 24% could have been from other mining hardware being turned on and tested. Also if people are getting S3's and the parts smell brand new, then that's another indication that haven't mined with the S3's. It would take multiple weeks of running the S3's for the difficulty to raise 24%. I would think a couple weeks worth of use would be noticed by customers receiving their miners.