(d) In those jurisdictions where, prior to January 1, 1990, the local ordinance did not allow the restoration of annual rent adjustment, once the owner is in compliance with this section the local agency may phase in any increase in rent caused by the restoration of the annual rent adjustments that is in excess of 20 percent over the rent previously paid by the tenant, in equal installments over three years, if the tenant demonstrates undue financial hardship due to the restoration of the full annual rent adjustments. This subdivision shall remain operative only until January 1, 1993, unless a later enacted statute which is chaptered by January 1, 1993, deletes or extends that date.