It only means that the Affidavit giving the particulars of assets, income etc., need not be filed along with the Application u/s 125 Cr.PC for maintenance.
Similarly, the Respondent need not file the Affidavit giving the particulars of assets, income etc., at the time of filing Written Statement.
But, once the main application u/s. 125 Cr.PC., the written statement by the Respondent and Rejoinder by the Applicant seeking maintenance stands filed (i.e. pleadings are completed), then the Applicant seeking maintenance and the Respondent have to file the prescribed Affidavit.