PTR/rDNS request

When calling sales to order Static IP's on my ATT Fiber line, the sales person was unable to add the service without sending out a tech.  This caused me to go to Tech Support to order the IP's.  He was successfully able to provide my IP's without any fuss.  When i asked him to also submit an rDNS request, he didn't know really what i was talking about.  He tried several times to refer/transfer me to ConnecTech, however i used to work for their t2 department, and on the connectech team.  I tried to get him to get me to the department that can fill out the form, however he wouldn't.  I was able to find online att.net/dns, and it looks exactly like what i'm looking for, however there is the folllowing blerb that makes me nervous:

There is a $50 charge per domain name for change requests made on an existing domain name, after the initial DNS request. 

There is a $100 charge for adding an additional domain name. 

If i'm only doing a PTR record, is there still a charge after the inital request? what if i don't know what i want to name my rDNS on the other IP's yet and may at some later date?  i don't want to be charged for PTR Record changes, as i am completely unable to make them without att's assistance.  Isn't that part of the $15/mo i'm paying for them in the first place?