Hi Kyle,
Did you manage to resolve this after?
I have been playing about with the settings also and it seems it can be slightly "hit and miss".
I set the parameter 2011 to "Request" and made it consider the "Company" in the request as the determining attribute. I also enabled it for the request type 001 (new user), so default role X is only considered when creating new user accounts for Company X etc, with default role Y considered for new users in Company Y (this is done on the NWBC side).
I don't think it is possible to send a blank request in hope for the default roles to be only assigned. Upon submission, the ARM tool will look at the request being submitted and tell you to put in items. The solution may be to assign a "System" (rather than a role), but this could well require tweaking/redesigning both your initiator and workflow to cater for "System-only" access requests.
Hope the reply/answer helps.
all the best