Does anyone else ever had the problem of TMPEGenc producing files that are too large?

I calculate the desired bitrate in DVTool. When I use that bitrate in TMPEGenc, it produces a MPEG-1 file that is way larger than what was calculated. It happens every time, using different sources (AVI, mpg, frameserve), CBR, VBR, etc... I've even tried different versions of TMPEG.

However, if I encode with Panasonic with the same bitrate, it's OK.

Does anyone have any ideas? I'd prefer to use TMPEG as it has more options and produces (to my eyes) better results. And of course is free.

Thanks,