Any person aggrieved by a determination as to eligibility for a payment authorized by the Relocation Assistance Act or as to the amount of the payment may appeal the determination. The appeal shall be in accordance with the Administrative Procedure Act. Nothing in the Relocation Assistance Act shall be construed as creating in any condemnation proceedings brought under the power of eminent domain any element of value or damage not in existence immediately prior to April 2, 1989.