This was probably the only way to resolve this: you'd have thought that the SQA would have realised early on that trying to handle results based on professional judgement, to try and make them comparable with previous years that were based on exams, was a square peg/round hole risk and, mixing metaphors, was a classic example of trying to treat oranges as if they were apples.
It is a U-turn, but those affected won't care about that once the revised grades are released, and I'd imagine the since the SNP were prepared to say they 'got it wrong', rather than keep on trying to defend the indefensible, voters might not hold it against them for too long - whether Swinney can survive is another matter.
I'm watching the debate in Holyrood just now and thought some of the Tory questions were less robust than I'd have expected - but of course the A level results due in England this week will, it has been reported, produce an even greater incidence of teacher-estimated grades being revised downwards and, if so, I wonder if the events here in Scotland will influence the reaction in England.