Yes, correcting for errors at input and end part of the cycle is how they claim MQA sounds better They have a "generic" mode when you don’t have access to the original A/D to measure though, so it IS possible to take a Redbook CD track, MQA it and have the MQA light turn on, but in theory it’s not as good as being able to go back to the source knowing the characteristics of the A/D converters.
Where it gets further very difficult is that to do this the most accurate way you should apply MQA fixes to EACH source track, not the 2 channel mix down. You have to correct the multi-track originals, and then remix THAT to get a new 2-channel mix down. So there is no guarantee anymore that the recording master has taken exactly the same settings. This is why I think HDT is calling it a "remix."
Where it gets further very difficult is that to do this the most accurate way you should apply MQA fixes to EACH source track, not the 2 channel mix down. You have to correct the multi-track originals, and then remix THAT to get a new 2-channel mix down. So there is no guarantee anymore that the recording master has taken exactly the same settings. This is why I think HDT is calling it a "remix."