; and (ii) voluntary contributions from digital music providers and significant nonblanket licensees as may be agreed with copyright owners. (B) Voluntary contributions (i) Agreements concerning contributions Except as provided in clause (ii), voluntary contributions by digital music providers and significant nonblanket licensees shall be determined by private negotiation and agreement, and the following conditions apply: (I) The date and amount of each voluntary contribution to the mechanical licensing collective shall be documented in a writing signed by an authorized agent of the mechanical licensing collective and the contributing party. (II) Such agreement shall be made available as required in proceedings before the Copyright Royalty Judges to establish or adjust the administrative assessment in accordance with applicable statutory and regulatory provisions and rulings of the Copyright Royalty Judges. (ii) Treatment of contributions Each such voluntary contribution shall be treated for purposes of an administrative assessment proceeding as an offset to the collective total costs that would otherwise be recovered through the administrative assessment. Any allocation or reallocation of voluntary contributions between or among individual digital music providers or significant nonblanket licensees shall be a matter of private negotiation and agreement among such parties and outside the scope of the administrative assessment proceeding. (C) Interim application of accrued royalties In the event that the administrative assessment, together with any funding from voluntary contributions as provided in subparagraphs (A) and (B), is inadequate to cover current collective total costs, the collective, with approval of its board of directors, may apply unclaimed accrued royalties on an interim basis to defray such costs, subject to future reimbursement of such royalties from future collections of the assessment. (D) Determination of administrative assessment (i) Administrative assessment to cover collective total costs