funci Hi
Have also tried to add extra fields to replicate the steps outlined in other forum topic and they are working fine as envisaged on local install. Also, Kindly ensure if you have added the code along with other PHP code as suggested through zipped package attached in default.php file. Ref: Screenshot
Local install article page where it appears fine
If still unable to get the extra field to show, Please share the site creditionals in order to investigate the same