Correct, the model was the same for a while where you purchase either CUWL licenses or UCL licenses, however until version 9 it was not tracked properly in CUCM as everything was being converted to DLUs. as of 9.0 it is nicely tracked now.
CUWL Standard does not provide PRO features, PRO is PRO and Standard is Standard. If you can access partner pages refer to this CUWL ordering guide for more details:
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.