Any agreement entered into under subsection (a) of this section, and any benefit schedule prescribed under subsection (b) of this section, shall not require the expenditure of funds in excess of amounts authorized to be appropriated under section
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(f)(1)(C) of this title, nor shall any individual employee receive benefits in excess of $20,000 under such agreement or benefit schedule. No benefits or assistance may be provided under any agreement entered into or benefit schedule prescribed under this section after April 1, 1984.