Judgment, Supreme Court, New York County (Asch, J.), entered November 17, 1981 dismissing the petition which sought to set *732aside respondent’s determination that the landlord include a two-month rent concession in all renewal leases executed with the tenant Rosenberg, affirmed, without costs or disbursements. The initial lease, executed on February 1, 1966 for a three-year term, contained a rider which provided for a concession whereby the tenant was not required to pay rent for the first two months of the lease term. None of the renewal leases contained a similar provision. On February 3, 1978 the tenant filed a complaint of rent overcharge with the Conciliation and Appeals Board (C.A.B.), contending that he was overcharged during three renewal lease terms because the owner, in calculating rent for such leases, failed to take into account the initial lease’s two-month rent concession. Before the board, the present owner, which took title to the premises on February 6,1976, took the position, as it does now, that it was the intention of the parties to the original lease that the two-month rent concession be a “one-time only” concession to induce the tenant to rent the apartment and' that the concession expired with the initial lease. The board found that pursuant to section 60 of the Code of the Rent Stabilization Association of New York City, Inc. (Code), the owner was required to include in each renewal lease a concession of rent for the first two months of the lease term. Under the Rent Stabilization Law the lawful stabilized rent is equal to the rent charged on the lease date, i.e., May 31, 1968, plus any increases authorized by the Rent Guidelines Board for vacancy or renewal leases. (Administrative Code of City of New York, § YY51-6.0, subd c; Code, § 60.) The Rent Stabilization Law requires that the Code promulgated thereunder contain provisions to prevent any evasion of the lawful stabilized rent and other provisions of the law either directly or indirectly, such as by reducing services or altering the lease agreement to the detriment of the tenant. (Administrative Code, § YY51-6.0, subd c, par [5].) Section 60 of the Code implements this requirement in mandating that, except for authorized rent increases, renewal leases be offered on the same terms and conditions as the expiring lease. (See Matter of East 56th Plaza v New York City Conciliation & Appeals Bd., 56 NY2d 544.) The board’s interpretation of the Code has a rational basis and although we might have reached a different conclusion, this court may not substitute its judgment for that of the board. (Matter of Park East Land Corp. v Finkelstein, 299 NY 70, 75.) Moreover, courts have repeatedly upheld orders of the board which required owners, pursuant to section 60 of the Code, to include in renewal leases conditions contained in the expiring lease. In Matter of La Barbera v Housing & Dev. Auth. of City of N. Y. (44 AD2d 835), the Second Department upheld a C.A.B. order requiring the owner to include in the renewal lease a provision for a one month’s rent concession for each year of the lease term, where the initial lease provided for such a concession. (See, also, Matter of Kliegman v McGoldrick, 285 App Div 1064.) The tenant’s failure to question the rent in the three previous renewals does.not amount to a waiver. Section 11 of the Code provides: “An agreement by the tenant to waive the benefit of any provision of the Rent Stabilization Law or this Code shall be void.” What a tenant cannot do by agreement he cannot accomplish by inadvertence. Moreover, section 10 of the Code provides that any lease provisions inconsistent with the Rent Stabilization Law or the Code shall be suspended. Inasmuch as the effect of the renewal leases was to alter the formula by which the rent was initially established, its provisions were inconsistent with the Code. Nor do we find laches available as a defense, since the courts must use the Statute of Limitations as a guide in determining a motion to dismiss for laches (Schreier v Cummings, 250 App Div 808), and section YY51-6.0 (subd c, par [3]) of the Administrative Code requires that landlords make allowance to provide cash refunds or credits for any rent paid since 1969 in excess of the fair rent for the *733apartment. No time limitation is established. Moreover, the landlord has not been prejudiced by the tenant’s delay in seeking reformation of the lease. (See Marcus v Village of Mamaroneck, 283 NY 325.) The only sums the landlord will have to repay to the tenant are those which it collected as rent after taking title to the building. Concur —■ Murphy, P. J., Sullivan, Ross and Milonas, JJ.