This example changes the default time that the Form Action Automation will respond when it is responding in x days, months or years before or after a static date. The default is for it to respond at midnight on said static date. This example would change the default time to 10 AM.

add_filter( 'frm_autoresponder_time', 'change_default_autoresponder_time', 10, 2 );
function change_default_autoresponder_time( $time, $args ) {
  $time = '10:00:00';
  return $time;
}

This example will allow for the autoresponder for a single Form Action be based on a Time field in a form. NOTE: If your time field is using AM/PM formatting, the code below may need to be adjusted.

add_filter( 'frm_autoresponder_time', 'change_default_autoresponder_time', 10, 2 );
function change_default_autoresponder_time( $time, $args ) {
  $time_field_id = 25; //replace 25 with the ID of your Time field
  $form_action_id = 250; //replace 250 with your form Action ID
  if ( $args['action']->ID == $form_action_id && isset( $args['entry']->metas[ $time_field_id ] ) ) { 
    $time = $args['entry']->metas[ $time_field_id ] . ':00'; // this line may need some adjustments if you are using times with AM/PM
  }
  return $time;
}