(1) A member whom the retirement board finds to have become totally and permanently disabled from any gainful employment by reason of personal injury or mental or physical illness while serving as an employee of that reporting unit shall receive a duty disability retirement allowance if all of the following requirements are met:

  (a) The member has not met age and service requirements of section 81(1)(a) or (b) or, if the member first became a member on or after July 1, 2010, the member has not met age and service requirements of section 81c(1).

  (b) The member is in receipt of weekly worker’s disability compensation on account of employment by a reporting unit.

  (c) The member or reporting unit makes written application to the retirement board not more than 12 months after the date the member terminated public school employment.

  (d) The member undergoes an examination by 1 or more practicing physicians or medical officers designated by the retirement board who certify to the retirement board that the member is totally and permanently disabled for performing the duties for the member’s position for which the member is qualified by reason of training, or experience, or both.

  (2) The member’s duty disability retirement allowance shall be computed pursuant to section 84. The effective date of the duty disability retirant’s allowance shall be the first of the month following the month in which the member terminates employment and is in receipt of weekly worker’s disability compensation. The years of service credit used in computing the retirant’s duty disability retirement allowance shall not be less than 10 years. If the member has less than 5 consecutive years of credited service, the average of the member’s annual compensation shall be used.

  (3) Upon recovery and return to reporting unit service or upon termination of the statutory period for the payment of a disability retirant’s worker’s disability compensation, if any, arising on account of the retirant’s reporting unit service, the retirant shall be given service credit for the period and the retirant’s disability retirement allowance shall be adjusted to include the additional credit.