Difficulty right now is scaling according to the NW hashrate.

NH was exploiting earlier. NH used to come when diff was too low 200k or so and when Network hashrate was few MH/s (4-5) and mine with several MH of hash power (100+) spiking the difficulty to 6000K+ and then leave the Network with 4-5 MH/s again but the difficulty was still 6000K+ and 4-5 MH/s on Network hashpower took several hours to mine blocks and earlier difficulty adjustment required some x blocks to be mined before the difficulty gets readjusted.

The dev's improved the difficulty algorithm to cater to this problem and the difficulty adjust much faster and in accordance to Network hashrate