At the time of this writing (v8.1.0), there is no way to specify the MPP ports, it can only be changed by also changing the base TDV port and letting the MPP port assignments follow suit as described above. Thus there will always be the span of 100 away from TDV's base port. Manually editing the ports mentioned in the /apps/drill/conf/drill-override.conf file will not alter the behavior.
We can suggest that you file a feature request at:
https://ideas.tibco.com/portal_session/newto advocate for the ability to specify the MPP ports, if the offset of 100 is impractical for your environment.