Audio and Video - best practice?

I have been making a showreel, where I took video of a live performance and recorded the PA output from the desk into CbB where I could later add eq, reverb and a few other FX.  I imported the video into CbB and replaced the audio from the video with the audio I had recorded into CbB.   I then exported the video with the new audio.  Which works fine in Windows movie maker, but in Lightworks the audio runs too quickly.
 
So is it best to export only the audio from CbC and do the synch in LTWKS?   Changing the audio in CbB gave me absolute alignment, in LWKS it's not as accurate - the lowest level of detail seems to be a single frame.  I am wondering if the reason that the audio runs too quickly in LWKS is becuase there's a something like a sample rate mismatch between CbB & LWKS?
 
Any thoughts?