(B) Exception.--Notwithstanding the restriction in subparagraph (A)(iii), a local educational agency may reduce the level of expenditures where such reduction is attributable to--

(i) the voluntary departure, by retirement or otherwise, or departure for just cause, of special education personnel;

(ii) a decrease in the enrollment of children with disabilities;

(iii) the termination of the obligation of the agency, consistent with this part, to provide a program of special education to a particular child with a disability that is an exceptionally costly program, as determined by the State educational agency, because the child--

(I) has left the jurisdiction of the agency;

(II) has reached the age at which the obligation of the agency to provide a free appropriate public education to the child has terminated; or

(III) no longer needs such program of special education; or

(iv) the termination of costly expenditures for long-term purchases, such as the acquisition of equipment or the construction of school facilities.