distribution license

Hello I'm a small IT consultant that provides support to different offices. I would like to control the installation of software on the computers (ie all the same version and to try keep the end users from running software installs). I have setup a WSUS server for distributing windows updates and installed the WSUS Package Publisher for deploying other software updates. I previously had it working with the flash player updates using the scup url which no longer works. I realize that you need to apply for a distribution license but I need to understand how it will apply to me. Its not mandatory that I use it this way but it does help from an IT admin point of view. Does each office need to apply for a license? Is this something that I should even pursue? I didn't see any reference for IT admins distributing to the end users in an office type setting. Thanks so much for clearing this up.