①If grounds have occurred based on which the beneficiary of an employees' disability pension (excluding the employees' disability pension of a beneficiary who has continuously had a disability of a degree of severity that is not classified as Grade 1 or Grade 2 of the disability grades from the time when the person acquired the right to receive benefits; the same applies hereinafter in this and the following Article, Article 52, paragraph (4), Article 52-2, and the proviso to Article 54, paragraph (2)) is to be paid further employees' disability pension, the employees' disability pension is paid in accordance with the severity of the beneficiary's disabilities stemming from a combination of the beneficiary's previous and subsequent disabilities.

②If the beneficiary of an employees' disability pension has, pursuant to the provisions of the preceding paragraph, acquired a right to benefits under an employees' disability pension for the severity of the beneficiary's disabilities stemming from a combination of the beneficiary's previous and subsequent disabilities, the beneficiary's previous right to benefits under the employees' disability pension ceases to exist.