The department may enter into agreements with Indian tribes to provide for the refunding of the tax imposed under s. 139.76. If the department enters into an agreement with an Indian tribe, the agreement may provide for refunding 100 percent of that tax on tobacco products and vapor products sold on the tribal reservation to enrolled members of the tribe residing on the tribal reservation and may provide for refunding 50 percent of that tax on tobacco products and vapor products sold on the tribal reservation to persons who are not enrolled members of the tribe residing on the tribal reservation.