A lot of calculations done pretty fast. I don't think Jupiter and Neptune can be compared so directly - we have no idea at what clock speeds the Neptune chips will run. I am, however, almost certain it will not be the same clock as the Jupiters, so in essence we can't compare core-for-core performance.
Absolutely. There are a lot of things we STILL do not know. Instead of this being an attempt to show Neptune necessarily will hash at a theoretical 5TH, it's more meant as a counter to all the pseudo facts being thrown out in this clusterfuck of an over dramatic thread citing Neptune couldn't possibly ever ROI.
As others have said, we're not out of the woods yet.