-snip-
Why have the past few months processed 6 blocks rapidly then had a massive gap between the next one? What happened to average 10 mins per block? Looking at this, 120 minutes between six blocks is 20 minutes per block average, which is double the expected time.
Its the average of
the last* 2016 blocks that count. Should that average result in 20 minutes the difficulty will be lowered.
*correction, its not actually checked every new block, so "the last 2016" is not correct.