Now you're just trolling. Timestamps are set by miners and are not universally reliable, and in any event difficulty retargeting relies on the law of large numbers (ie. capacity for statistical variance has to exist).
Also hey, the last 5 Darkcoin blocks tell exactly the same story:
[1] [2] [3] [4] [5] Yep, your example was basically the same thing. Difficulty retargets slow. And the reward curve described in the whitepaper was taken into use after GPU miners started to appear, so the graph you posted does not use that formula at the beginning.