actually, he says that the engineer (bob ludwig) gave him both protools files and a 1/4" reel, so there's really no telling what bob put in between Pro Tools and the tape, since don wasn't at the sessions.

my meager understanding of the subject is this:

yes, you can take something recorded digitally and bounce it to analog and it will affect the sound. i believe it gives it a different eq curve, rolling off highs for a sound some would call "warmer". there are also digital plug-ins that emulate this eq curve.

also, of course, if you hit the tape hard you will get certain kinds of compression and/or distortion.

you can also bounce this result back to digital if need be, and it shouldn't change the eq curve back. so some people bounce their final digital mix to analog and back to "warm" things up. i think there are devices specifically made with this in mind.

WoP is generally right...say you record something digitally at 24 bit 192k, then the result is an incredibly accurate representation of what went into the mixer. many people do not like this sound, and prefer the sonic influence of the tape machine in addition to whatever other manipulation has been done to the sound. so by combining the two, you can use the editing advantages of digital, then when you're happy with the arrangement and whatever, fly either the multitrack, or the 2 track mix to a tape machine, then back into the digital domain (which now contains a very accurate representation of your stuff + tapey goodness) for mastering. alternatively, one could also master off the tapes directly if they had the appropriate equipment.