Do remeber every other year the exam was out of 75 marks, this year out of 70 therfore the skew of marks would be positive. Thefore the Grade a boundry could vary and fluctuate between 52-62 the confidence interval would be large, as it anyones game. As i stated, most schools are not prepared, theres uncertainty about exam structure, the gov have to look good ' The new exams have to be reflective of increasing standards', the Exam boards do not have historical data to go by, so tbey can only estimate, (Do a little search for ofqual grade predictions) so they may have predicted an A is 57 which could be the case, but depends on the noise of the data, and how much other factors intervenes with the real value.