If an authority is the owner or operator of a housing project that includes units for persons of other than low or moderate income, the operating expenses of that project (or of all such projects, together, owned or operated by the authority) shall be met entirely from rents from the project (or projects) together with any rent subsidies provided to low income tenants in the project (or projects).  No rent subsidy may be provided to any tenant who is not a person of low income, and no rent subsidy may be paid from bond proceeds. (1987, c. 464, s. 4.)