Wouldn't it have been better to use the 5.1 mixes of the foreign tracks for this. I know that the French & German 5.1 tracks off the 2004 DVDs contain a lot of the mono mix as their basis. You can strip them to separate tracks and use the left, right & surround tracks for the mix and easily add the English dialogue, including lines from the mono mix, but still end up with a good stereo mix . In the clip you posted it is very noticable when you drop the lines from the mono mix in. You can hear the stereo field expand and contract each time its dropped in and the EQ of the different tracks needs balancing too.. This can be eliminated quite easily by using the foreign 5.1 mixes.