(2) For buildings receiving benefits pursuant to section 421-a of the Real Property Tax Law and the regulations promulgated pursuant thereto, such clauses may provide for an annual or other periodic rent increase over the initial rent at an average rate of not more than 2.2 percent of the amount of such initial rent per annum not to exceed the maximum cumulative amount, if any, permitted under the 421-a program rules and regulations. After the tax benefits end, such additional 2.2 percent charges shall no longer be added but the owner may continue to collect the cumulative 2.2 percent increases charged prior to the termination of said tax benefits. Any lease containing the aforementioned provision shall also include a rider with an endorsement signed by the tenant acknowledging the owner's right to include such provision and to collect such rent increase for the tax benefit period. Such rider shall state the approximate date of the expiration of such tax benefits.
(3) Nothing in paragraph (2) of this subdivision shall prohibit the inclusion of a lease provision for an annual or other periodic rent increase over the legal regulated rent at such rate of rental increase as is provided for and authorized by section 423 of the Real Property Tax Law. Such additional charges pursuant to such section 423 shall no longer be added after the tax benefits end. Any lease containing the aforementioned provision shall also include a rider with an endorsement signed by the tenant acknowledging the owner's right to include such provision and to collect such rent increase for the tax benefit period. Such rider shall state the approximate date of the expiration of such tax benefits.