Today I have noticed a significant decline in the rating of almost every problem. For example, The Three Red Squares had a rating near about 2150 yesterday and now it's rating has dropped to 1785.6. And the problems which I surely remember were of level 5 ,like, Push Hard!,Optimise The Students etc. are now Level 4. Actually I am having a hard time to find a level 5 problem. Can anyone tell me why is that happening? Is that a change meant to "increase the difficulty level" of brilliant or something like that?