(1) All industrial improvements shall be valued by the use of the Montana Appraisal Manual.

(2) The department appraiser shall use their best judgment to establish the effective age by examining the condition, desirability and utility of the property.

(3) Upon the determination of the property's effective age, it shall be depreciated on an age/life basis according to the internal program schedules of the Montana Appraisal Manual.

(4) If the reproduction cost of the property is not listed, or is not accurately listed in the Montana Appraisal Manual for the specific property being appraised, then the department may use other appropriate cost manuals such as "Means" or "Marshall Valuation Service" to obtain the best estimate of reproduction cost. This reproduction cost would be depreciated on an age/life basis to arrive at market value for assessment purposes.

(5) If appropriate, the department may apply the approaches to valuation described in ARM 42.22.1309.