Within the boundaries of Virgin Islands National Park as established and adjusted pursuant to sections
398 and
398a of this title, and as revised by sections
398c to
398f of this title, the Secretary of the Interior is authorized to acquire lands, waters, and interests therein by purchase, exchange or donation or with donated funds. In acquiring such lands, up to 6.6 acres, the Secretary may, when agreed upon by the landowner involved, defer payment or schedule payments over a period of ten years and pay interest on the unpaid balance at a rate not exceeding the current prevailing commercial rate.