<Page>


Exhibit 10(b)(4)

                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350,
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002


         In connection with the Report of Cohen & Steers Advantage Income Realty
Fund, Inc. (the "Company") on Form N-CSR for the fiscal year ended December 31,
2002 as filed with the Securities and Exchange Commission on the date hereof
(the "Report"), I, Martin Cohen , Chief Financial Officer of the Company,
certify, pursuant to 18 U.S.C. 'SS' 1350, as adopted pursuant to Section 906 of
the Sarbanes-Oxley Act of 2002, that:

         (1) The Report fully complies with the requirements of Section 13(a) or
15(d) of the Securities Exchange Act of 1934; and

         (2) The information contained in the Report fairly presents, in all
material respects, the financial condition and results of operations of the
Company.


                                  /s/ Martin Cohen
                                  ----------------------------
                                  Martin Cohen
                                  Chief Financial Officer
                                  Date: February 26, 2003