(h) Any owner undertaking to abate or contain dangerous levels of lead in any dwelling unit may, at the owner's option, reasonably delay the commencement of the tenancy until a letter of compliance or interim control certificate has been issued; provided, that no duly executed lease exists between owner and tenant; and provided, further, that no such delay shall exceed thirty days. During any such period of delay of occupancy the prospective tenant shall bear any living expenses. Should the owner decide to bring any residential premises into compliance with the provisions of sections one hundred and eighty-nine A to one hundred and ninety-nine B, inclusive, while a tenant is occupying a dwelling unit, the owner shall have the right to move the tenant to a substitute dwelling unit upon reasonable notice; provided, however, that the owner pays reasonable moving expenses and any use and occupancy charges for a substitute dwelling unit which exceed the rent for the vacated dwelling unit for which the tenant remains responsible. A substitute dwelling unit shall be defined as one that does not cause undue economic or personal hardship to the tenant. If the tenant fails to accept the substitute dwelling unit selected by the owner during such period of time reasonably required to bring the vacated dwelling unit into compliance with the provisions of sections one hundred and eighty-nine A to one hundred and ninety-nine B, inclusive, the owner shall have no obligation to reimburse the tenant for any expense or inconvenience other than moving expenses and any use and occupancy charges for the substitute dwelling unit selected by the owner which may exceed the rent for the vacated dwelling unit.