Application for aid may be made within 60 days prior to the date on which the applicant meets the technical requirements for such aid which have to do with factors other than need.

Application made on behalf of a child deprived of parental support because of separation or desertion may be made within 60 days prior to the date on which he will become eligible.

The application shall be promptly investigated and acted upon, but in no event shall the aid, if granted, begin as of a date prior to the date on which he meets such requirements.