No, you cannot log more points. You can create as many data log models as you want, but only 1 can run in a project.
Yes, that is the max points for the total of all your registers/tags.
You can look at the data log as a historical trend. It's the only way to see the data on the PV+.
If you want to log data to a text file (CSV) then use the Datastore ActiveX control. That only has a limit on the storage space, but will NOT work with the trend display.
I wish they would just add all the features of the Datastore ActiveX into the Data Log models.