Let me try to explain my understanding on how time machine works.
Since i already have a full backup of my disk, any changes or additions i make on my mac would result to "something" being backed up on the next time machine backup. Lets say i install an application that is 5 GB. The next backup i make on time machine should only back up that 5 GB of data. So I would assume that if i was to remove a program from my mac, it would result in nothing being backup. Today, I removed several programs, videos, etc. and started time machine and it started preparing a 122GB back-up! which doesn't equate to a new full backup since my drive is + 300GB.
So I'm confused....