MINDAYS is applicable only for user ACIDs and does not apply when administrative ACIDs change their password at signon . MINDAYS is not applicable to users who have a non-expiring password.
When you need to change the EXPDT to a CA 1 Keyword value you need to use the actual keyword, not the date that you would put in your JCL. Here is a list of the keywords and an example of the TMSUPDTE control statements. TMSUPDTE...