1. the best way of authoring a DVD or BD is to encode your assets !!prior!! you start authoring. forget about automatically set bitrates and automated transcodings – do it your own!
2. if you have a duration of 105min. that will result to 5,5Mbit/s target-rate (if you are using AC-3 audio@192kbit/s) to not overfill your disc.
encore do not use CBR, it will use a VBR-transcoding, so if you set your transcoding to 9.4Mbit/s I guess it will be using 5.0Mbit/s, so it will not fill the disc completely. 9.4MBit/s is the peak-rate for your transcoding-setting.
3. again – 9.4 Mbit/s is much to high for DVD-R/+R (even if it is peak-rate-value) , if you had luck or not, this could only be used with replicated DVDs.
in your specific case 9.4Mbit/s would result in too much date for your DVD-5.
you´ve asked for reasons – here they are.
cheers
danny