The remoterig DDNS status website reports:
RRC DynDns Result
User   ws1216H-3648
Host Name   xxxxxx.ddns.webswitch.se
IP Address   50.50.248.72
Last update   2020-07-12 06:07:37
Update count   20
In addition, the AS1289 "System Info" reports:
Max available memory   18301
DNS status   OK, remoterig.com = 213.180.92.125
Dynamic DNS status   Unknown
Ping status (watchdog)   Off
Active profile   Default
Last WD Reset   1
TCP Error counter   0
Webserver   1
From time to time the Dynamic DNS status shows "Error, code = 103".  
How do I use the same DDNS address as the RRC-1258 as you suggest?  If you mean to use the same Dynamic DNS hostname, ddns.remoterig.com, I am unable to change that in the "Dynamic DDNS settings/ Dynamic DNS hostname".  
73, Dean