BW authorizations in BPS layout

Dear all,

My question may seem basic, but I don't have any experience with authorizations.

I need to use already existing BW authorizations in my BPS layouts, so well, I created auth. variables on the needed characteristics and assigned it to my layout.

==> nothing changes when I'm launching the layout.

I wonder if I need to ask the modification of the already existing BW roles in order to add field ACTVT? Will this have an impact on already existing BW reports for the users?

Also, does something need to be done in RSSM (or other T-code) in order to activate the auth. for my planning cubes?

Thank you in advance for your help!!