Tip pads are for ferrule protection.
Originally, they were used mostly with ivory ferrules. They don't have any significance in the way the shaft or tip plays, they're really just there to protect the ferrule.
Have you ever wondered why just the top of the tip mushrooms? I mean, the bottom of the tip goes through the same stress as the top does. If you smash a marshmallow, it smashes and spreads at both ends. The reason a tip doesn't spread at the bottom is because it's glued to the ferrule, and the ferrule would have to spread along with it. Ivory is subject to cracking under this stress. Most plastic ferrules today will keep the "mushrooming" from happening at the bottom, so no pad is needed. However, some ferrules like ivory or our laminated maple ferrules need a little help in controlling the bottom of the tip wanting to spread. So, we put pads between the tip and the ferrule. Most use a vulcanized paper, but we use a carbon fiber pad to protect our ferrules.
