I purchased your add-on and I'm having an issue with permissions.
In testing I setup two categories, with identical permissions, one minute, one thread for the same user group. When I bump a thread in the first category, it prevents me from bumping a thread in the second category. I then set different bump times for each category, however both categories were locked to the first timer.
I then applied 1min, 1 thread to one user group for the first category and 5min, 1 thread to a second user group for the second category. The user is a member of both user groups. When I bumped one thread, any further attempts gave the one minute timer. In the second category it would not let me bump any threads, and gave the 5 minute timer instead.