2 mistakes.  1 you assume BFL will actually deliver by january/februrary, that's a brave assumption.

Hash rate will continue to rise exponentially, but not as fast as in recent months.  The growth we're seeing is ASIC chips starting to catch up with mainstream chip technology.  Mainstream CPUs have been on the 22nm process since Q2 2012, Bitcoin ASICS aren't even there yet.

Intel is projecting 5nm technology in 2019, Bitcoin ASIC could well be caught up by then.

So we will still see exponential growth, but that growth curve will slow the closer the ASICs get to the limits of current microprocessor technology.

I think we'll continue to see large jumps here and there over the next year, but the growth curve will become a bit more predictable as the hardware manufacturers establish themselves and begin consistent product R&D and delivery cycles.