I have been fighting with it for some days, but still can't figure out how it works.

In 20-59-14 UC license level, it has 3 options: soft phone/Deskset/softphone+deskset.
In 20-59-15 UC login mode, it has softphone and deskset 2 options.

How to decide which option to be used?

And UC suite client also has softphone and deskset options, it could login as a softphone even 20-59-15 is set as deskset.

I am totally lost, any help?