In addition to amounts otherwise authorized by this subchapter, the head of a displacing agency shall make a payment to or for any displaced person displaced from any dwelling not eligible to receive a payment under section 4623 of this title which dwelling was actually and lawfully occupied by such displaced person for not less than 90 days immediately prior to (1) the initiation of negotiations for acquisition of such dwelling, or (2) in any case in which displacement is not a direct result of acquisition, such other event as the head of the lead agency shall prescribe. Such payment shall consist of the amount necessary to enable such person to lease or rent for a period not to exceed 42 months, a comparable replacement dwelling, but not to exceed $7,200, as adjusted by regulation, in accordance with section 4633(d) of this title. At the discretion of the head of the displacing agency, a payment under this subsection may be made in periodic installments. Computation of a payment under this subsection to a low-income displaced person for a comparable replacement dwelling shall take into account such person’s income.

Any person eligible for a payment under subsection (a) of this section may elect to apply such payment to a down payment on, and other incidental expenses pursuant to, the purchase of a decent, safe, and sanitary replacement dwelling. Any such person may, at the discretion of the head of the displacing agency, be eligible under this subsection for the maximum payment allowed under subsection (a).