Notwithstanding any other provision of chapter 180, Oregon Laws 1953, chapter 401, Oregon Laws 1945, as amended, shall remain in full force and effect with respect to any employee of a public employer which heretofore withdrew from the Public Employees Retirement System pursuant to subsection (5) of section 8 of said law, as amended by section 1, chapter 322, Oregon Laws 1951, who did not sign the petition for such withdrawal. Such employee shall be and remain a member of the Public Employees Retirement System with full rights and benefits thereunder as if chapter 180, Oregon Laws 1953, had not been passed; and until the entire obligation of the public employer with respect to all such employees, as provided in chapter 401, Oregon Laws 1945, as amended, shall have been paid in full, such public employer shall continue to deduct from payrolls and transmit the contributions thereby required and make the matching contributions thereby required to the Public Employees Retirement Board created by ORS § 237.952 and such public employer shall remain liable to such Public Employees Retirement Board for all contributions required by such law together with interest thereon at the legal rate from the date of any delinquency. [1953 c.180 § 11]