I understand what you feel,but i think you’re using Premiere the wrong way.
You chose a DV format the export,then you must follow the DV rules,
Most of the DV playback device doesn’t support sample rate higher than 48KHz,and bitrate hight than 16bits
so if you export your project this way,it’s the FORMAT cut your rate down,not Premiere.
My suggestion is to export the video/audio seperatly,you will see the right setting when export audio.
Then you might sych them back together using your DVD authorizing software.