Unexpected Groove Quantize Behavior

So, I'm using the following method (as described in the reference manual) to align a "sloppy" midi track with a "good" one:

Aligning sloppy tracks with a good one. Select the portion of the “good” track that you want to apply to the “sloppy” tracks and copy it to the Clipboard. Select the portion of the sloppy tracks you want to modify. Choose Process > Groove Quantize, choose the Clipboard as the groove source, and click OK.

The problem is that, even when I set the timing slider to 100%, it doesn't line up perfectly. This can be verified by zooming in in the PRV. Now, I don't actually want the two tracks to be totally locked to each other; however, it would be comforting to know that, if I did want to set the timing to 100%, it worked as expected. Likewise, if it doesn't get the 100% setting correct, how can I be sure it's getting a setting of 25% or 50% correct?

Is there something I'm misunderstanding about how this should function? Is anyone else having this experience? Thanks in advance for any feedback.