Art. 39 Verordnung No. 1 zum SchKG; standing of the debt collection office and entitlement to a detailed cost statement after foreclosure sale; the office may complain against a supervisory decision ordering it to issue a detailed cost account where the exception under Art. 39 directly affects its legal position. Purchasers at a forced sale are not “parties” within the meaning of Art. 39, nor may they invoke Art. 8 SchKG, if the auction costs are borne by the realization proceeds and not charged to them. Any transferred right to information through reimbursement of costs presupposes prior demand vis-à-vis the creditor; the office cannot be compelled anew once the creditor has already received the detailed account.
C. Diesen Entscheid hat das Betreibungsamt Rheinfelden innert Frist an das Bundesgericht weitergezogen, mit dem Begehren um Aufhebung. Die obere kantonale Aufsichtsbehörde hat von Gegenbemerkungen abgesehen. Die Schuldbetreibungs und Konkurskammer zieht in Erwägung: