"link to cost center/activity types" in costing tab of workcenter

Hi experts,

I have a doubt about the "activity types" defined in the "link to cost center / activity types" in costing tab of work center (attached screen) in which I am not sure what is the use of this table in the work center defined for PS? Is it used in PS or it is for other modules?

As I know, we define the default activity type in the "ActType Int.Proc." field and all other activity types are accessible in T.code CJ20N for search and selection. So what is above mentioned table for activity types in the work center for?

Note that I found only one tread about this but it goes to 2007:

Work Center & Activity type in PS

Please clear me on this issue.

Thanks in advance

majid