Quick question about audio...

[MiyaDV]

Hey,

I've always finished most of my videos in this order:
Render video lossless > Encode to mp4 in megui
Render audio lossless > Encode to m4a in itunes (note I tried NERO AAC m4a too same result)
then I mux them with YAMB

After I encode the audio though, in YAMB it showed it was 4:550mili seconds
my original .wav file was 4:500miliseconds
so I brought them in Vegas and all the audio matched up perfect, except there was an extra 2miliseconds at very end added onto the audio (this shouldn't hurt muxing right?)
Anyway, after I muxed the video was 4:06 secs long, the lossless was 4:05 long
I thought I was noticing a little offsync in my video after, but I'm REALLY not sure lol It could be just that the lossless is much sharper... I'm over complicating something again ><