The first year a manufacturing facility is allowed an ad valorem exemption, the real property is to be designated as XM-1 on the assessment roll under homestead exemptions allowed. The second year the exemption is allowed, XM-2 will be shown under homestead exemptions allowed for that year. The third, fourth and fifth year, the designation will be XM-3, XM-4, and XM-5, respectively. The sixth year, no designation will be shown, and the property will be assessed and taxed as other property.
Okla. Admin. Code § 710:10-7-18