Sec. 8-73. Eviction of families having income over maximum limits. Waiver of eviction requirement. (a) A tenant in a moderate rental housing project shall vacate the dwelling unit occupied by such tenant not later than sixty days after the housing authority or developer has mailed to such tenant, properly addressed, postage prepaid, written notice that the annual income of such tenant's family, determined under section 8-72, is in excess of that permitted for continued occupancy of such dwelling unit under said section. Upon the failure of such tenant to vacate such dwelling unit on or before the expiration of such sixty-day period and as long as such tenant continues to occupy such dwelling unit after the expiration thereof, such tenant shall be obligated, notwithstanding the provisions of section 8-72, to pay to the authority or developer monthly as rent for such dwelling unit an amount equal to the going rental therefor as fixed by the authority or developer plus an amount equal to two per cent of the excess of the annual income of such family over that permitted for continued occupancy of such dwelling unit under section 8-72.