Where the amount of the original claim is greater than $5,000 but less than $10,000, the Collections Section with the approval of the Commissioner of Finance and Administration is authorized to accept compromises which provide for payment to the City of not less than 50 percent of the amount of the original claim.  Where the amount of the original claim is greater than $10,000, the Collections Section with the approval of the Commissioner of Finance and Administration is authorized to effect compromises which provide for payment to the City of not less than 75 percent of the original claim.  Where the amount of the original claim is greater than $5,000, lesser amounts than herein specified may be accepted in compromise only with Council approval.  The Collections Section with the approval of the Commissioner of Finance and Administration is authorized to cancel accounts receivable invoices of under $5,000 in amount or accept promissory notes or confessions of judgment where in the judgment of the Collections Section, substantial justice can thus be achieved.