Hmm, the bitrate options don't ring any bells I'm afraid.

I know there is an issue with dynamic range control with respect to dialogue normalisation - someone did a really good post on the Doom9 forums I found via a google search. It's all graphs with peaks and flat bits and I must admit I didn't follow all of it. I personally just fudge things by setting the dialogue normalisation to -31dB and the dynamic range control to 'none' - would your options be film light, film heavy, music light, music heavy?

Don't know if this helps at all:

Intervocative Forum

HTH

EDIT:

I've had a bit of a google and found this on the DVD Lab Forums:

DVD Lab Audio Ifo Edit

DVD Lab muxer supports:

16/48/2
16/96/2
24/48/2
24/96/2

I do not think it supports any 1 channel PCM. As far as input, user has to create a wav file to package the LPCM. Some audio software like CakeWalk's and Avid's load a long PAD chuck in the wav header, causing mux not detecting parameters correctly. Therefore user should keep the wav chucks as simple as possible.

This seems to be referring to PCM audio only, in which case the most common format is 16bit, 48Khz, 2 Channel. I do believe you can get some problems if you use 24bit PCM audio as some dvd players just clip the top 8 bits!!

I don't remember you saying about PCM so maybe you can ignore this?