Outstanding Volunteer Service Medal; any tips on how to get your unit to process it?

Congratulations on your volunteer service hours.
Does your higher command have a policy on the award?
I've seen commanders say you must give 500 hours in a year.
Have you provided documented hours?
The regulation is subjective. Or maybe no one knows how to process it because it doesn't get done often - Refer to the regulation, processing it is in there.

AR 600-8-2: c. There is no specific time period to qualify for award of the MOVSM; however, volunteer service must exceed 3 years and/or 500 hours of service. Approval authorities will ensure the service to be honored merits the special recognition afforded by this medal. The MOVSM is intended to recognize exceptional community support over time and not a single act or achievement. Further, it is intended to honor direct support of community activities. For the purpose of this award, attending membership meetings or social events of a community service group is not considered qualifying service, while manning a community crisis action telephone line is considered qualifying service. d. Approval authority for award of the MOVSM will be commanders (overseas and CONUS) serving in the rank of lieutenant colonel (LTC/O–5) or higher. Before the recommendation is forwarded to the award approval authority, the recommender must certify that the Service member meets the eligibility criteria for award of the MOVSM. Substantiating documentation, such as record of hours contributed, letters or certificates from activity supervisors, or other proof of the Service member’s volunteer services may be attached as enclosures to the recommendation.

Write it yourself and provide verification. Have your first line leader sign it and send it up. That's how I got mine.

SPC (Join to see) - Send me a private message with your hours sheet, name and contact information of the point of contact from the organization that you volunteered with, the name and email of your Company Commander and S1.