There are several important items to remember when updating the client feature set from SEPM:
1. Make sure you uncheck the "Maintain existing client features when updating". If you don't uncheck this then the clients will not do anything.
2. Make sure you uncheck the "Upgrade Schedule" checkbox. This way the clients chose to update their feature set immediately.
3. Make sure that the package you assign to the group is the same build number as the SEP clients in the group. If you assign an older build for this then the clients will ignore the settings.
4. Make sure you assign the correct bit rate (32bit vs. 64bit). Clients will only look at packages with their bit rate. If you assign a 64bit package, for example, and you have only 32bit clients then they will ignore the settings.
5. In most cases once the client has added or removed features you will need to reboot the client for the changes to be complete.