Calendar mechanics, as verified against published schedules: Copart and IAA operate weekly per-location sales with public preview windows; Manheim concentrates volume into dealer-only sale weeks at its major physical sites. The index tracks these because sale-week results are the root price data behind every retail asking price this site examines.
Analytical note: a seller's asking price is best read as wholesale comp plus recon plus margin. Two of those three numbers are public if you watch the calendars; the third becomes obvious.