So, there I was trying to rip a good sounding copy of the Mamas & the Papas' "Dedicated to the One I Love" single. I own two copies of it, neither in great condition. They are both mono US Dunhill 45-D-4077. Neither a reissue or anything, and the labels are marked the same. So, I rip them and am listening back to the b-side, 'Free Advice' on both of them to see which sounds better, when I realize... uhh, these are two totally different mono mixes!? And not like, "oh, this might possibly be a little different...", I mean, they are different. Besides the instruments being mixed at different volumes, one has a loud-as-can-be harmony from Denny on one line that the other is completely lacking. And, although, upon investigating further, the mono LP of 'Deliver' has this additional Denny harmony and the stereo LP does not, my 'Dedicated' 45 without the extra harmony is NOT a stereo fold-down, as it still has the added female harmony two lines later that only appears on the mono mixes!?! How can this be? The only physical difference I could find on the 45 was with the matrix number. On the 'Free Advice' side, one has just 01057 etched after the runout groove, the other has 01057-2. Similarly, the 'Dedicated' side has 00999-RE on the one, and 00999-RE-1 on the other. Other than that, they are marked exactly the same. Sooo, what gives? Anybody ever hear of anything like this?