Still it does not make sense. GHS/BTC price should theoretically follow the difficulty increase. So for 25% diff increase the price should have decreased by 25%, i.e. from 0.0075 to somewhere around 0.0052.. Even though it dropped to 0.006 for a minute, it is now around 0.0067 which is less that 10% drop.
This means the market is extremely optimistic about the ROI of their investment..