Along the same lines as Jeff .. just another way to do it;

On the selected track, Select the Whole track (hold CTRL + A) This sets the range for the edit.

Next
Select all tracks you want to edit (Hold CTRL and click each track number in the Tracks window, or hold Shift and click the first, then the last track if you want them all).
Make all desired tracks are all selected.

Go to CUT
Make sure the 'Use data filter' option is checked

In the resulting window deselect every option except Ctrl (control changes)
Set the Range for this to be 7 thru 7 (Volume control)
Cut them all.

Now you should have a clean volume slate and be able to change/save/review as desired.

There are many ways to get rid of these annoying settings.
I don't blame the authors of said MID files; as they had to choose something .. the MID file they saved simply has the mixer settings that sounded best on their system.

If this doesn't work you can also try cutting Control Change 11 (by changing the settings in the data filter when cutting)
CC 11 is for Expression, which is the secondary control change for volume.

CC7 (control change) limits the loudest volume.
CC 11 (Expression) limits the expressive range (inside the CC7 overall volume)

Hope I didn't confuse this .. but it's MIDI so it's all events you can control.

One other change you could make in RB is to go to
Options-Prefs-MIDI-MIDI Out and try unchecking the box for
Send Most Recent Patch/Wheel/Controller

The latter is kind of a Hackey way of handling it since it just stops the song from resetting from the last command, but if you press start those last commands are going to be sent anyway, so many times it's better to simply remove them and start fresh. Saving when changes are made

Make your sound your own!
.. I do not work here, but the benefits are still awesome