Coversion Causes Increase In Length??

[wee haggis]

For some reason when I convert a 1hr-58min Divx3 movie to SVCD using TMPGE,it comes out as 2hrs-3min???
I'm using the standard SVCD template on a NTSC Film using the bitrate calculator to fit on 2 cd's.
(I should also add that when I extract the audio as a WAV it stays at 1hr-58min)
Can anyone help?

[HighWired]

yes I rencoded some rips I made using tmpgenec and A bitrate calc it said the file should be 680mb but after rencoding it was still the original length then I'm not sure why but I simple remultiplexed it and Bingo 680mb so try remultiplexit and name it another file and compare sizes see if this works for you