Any member who was absent from work while receiving temporary total disability benefits pursuant to the provisions of chapter twenty-three of this code as a result of a compensable injury received in the course of and as a result of his or her employment with the covered employer, may purchase credited service for that time period or those time periods the member was absent from work as a result of a compensable injury and receiving temporary total disability benefits: Provided, That the member returned to work with his or her covered employer within one year following the cessation of temporary total disability benefits. The member desiring to purchase such credited service may do so only by lump sum payment from personal funds within two years of the end of the disability period for which credit is sought to be purchased: Provided, however, That in order to purchase such service credit, the member shall pay to the board his or her regular contribution and an equal amount that represents the employer's contribution, based on the salary the member was receiving immediately prior to having sustained such compensable injury: Provided further, That the member purchasing service credit under the provisions of this section may not be charged interest. The maximum number of years of service credit that may be purchased under this section shall not exceed two: And provided further, That each year purchased under this section shall count as a year of experience for purposes of the increment set forth in section two or section eight-a, article four, chapter eighteen-a of this code, as applicable.