(a) In establishing the upper income limits for a family of limited income, the Secretary shall consider factors including: (1) the income of the family available for housing; (2) the size of the family; (3) the cost and condition of available housing; (4) the ability of the family to compete in the private housing market; and (5) standards and definitions established for federal housing programs. (b) The limits established under subsection (a) of this section may vary for different: (1) types of housing; (2) programs of the Administration; and (3) areas of the State. (c) A limit established under subsection (a) of this section may be supplemented for a particular project.