If, the total assessed value of the real property for which
an exemption pursuant to Section 458 has been granted increases or
decreases as the result of a revaluation or update of assessments,
and a material change in level of assessment, as provided in Title
2 of Article 12 of Chapter 50-A of the Consolidated Laws of the State
of New York, is certified for the assessment roll pursuant to the
rules of the Commissioner of Taxation and Finance, the Assessor shall
increase or decrease the amount of such exemption by multiplying the
amount of such exemption by the change in level of assessment factor.