DV to DVD guide and audio sync

[Capsbackup]

I have followed the guide to back up my Hi-8/ Digital 8, NTSC camcorder tapes to DVD and am having the audio gradually going out of sync. Each is 60 min. tape that I capture thru Ulead Video Studio 11 to the Hard drive, and the DV file has perfect audio sync. I use Video Studio to save the PCM audio to a separate file and have tried both BeLight and Sonic Scenarist AC3 Encoder to convert the wav file to DD AC3. I follow the guide with AVISynth script and CCE 2.70 to convert to M2V video. I also use DVDMaestro to make into DVD. Both AC3 and M2V report exact same time amounts in DVDMaestro, so it does not appear to be dropped frames. When I use VS 11 to convert to a DVD file, the audio remains in perfect sync, but the video quality is not as good as with the CCE encode. Example of AVISynth script:

DirectShowSource("K:\Digital Video\9-16-91 to 7-4-92.avi")
ReInterpolate411()
SeparateFields()
ConvertToYV12()
odd=SelectOdd.Convolution3D(1,6,10,6,8,2.8,0)
evn=SelectEven.Convolution3D(1,6,10,6,8,2.8,0)
Interleave(evn,odd)
Weave()
DoubleWeave.SelectOdd()
If anyone has suggestions on what could be the problem or a solution it would be greatly appreciated!