If a trustee in a chapter 7 or 13 case does not have liquid funds available to pay the filing fee for an adversary proceeding, notice of removal, or a motion to convert or reopen a case, the fee may be deferred. The trustee shall pay the fee if and when estate funds become available. The trustee’s signature on a motion to defer the fee shall constitute a sworn statement that there are insufficient funds in the estate to pay the fee. Upon filing the motion, the trustee shall submit an order permitting the fee to be deferred.