"the resulting Merged Clip is vastly out of sync - by 3 to 100 seconds. Basically by the number of seconds the sound clip prelaps the video clip. "
how are you merging?
that sounds like you are merging using in point?
maybe merge by TC wont work with different TC rates, and it is defaulting to Merge by in-point
you could try placing in points on the clap, then merging by in-point.
i much prefer syncing my video and audio in a timeline.
when they are synced up,
i go through the timeline and LINK the clips,
then copy paste them into a new bin in the browser.
nick