they have zero need to build a more efficient miner and sell it to the public.
look at hashnest they still do well with the s-7
so if they build a s-11 it kills the s-7
the 67% s-7 number is the key to the s-11
when it gets to 90% and they do 1 more power cost drop to 6.5 cents
they will bring on the s-11
can you explain this please

the first number is -0.15120252 this is what my cost to buy and sell and own shares of the s-7 has been.
it is a negative number because I made a real profit of .151 btc up to now and I still own 765 gh of a s-7
the second number is .47742294 btc these are all the coins I mined with the different amounts of s-7 gh I owned
the last number is all the coin I spent to pay for power. 0.12682206
the number in blue 67.83% is what you pay in power now for an s-7 for every coin your s-7 earns you pay .6783 btc
s
So at the moment the s-7 still earns more money then it costs for power if you have 7 cent power cost. bitmain charges 7 cents for power.
there is no way bitmain is going to sell the s-11 or s-10 to us until the s-7 dies as a money maker.