Invisibility ruling

The core rules mention that invisibility grants a +20 or +40 bonus to stealth checks, as well as a -20 or -40 penalty to perception check. I believe these are redundant.

Noticing or pinpointing a visible object is DC 0 plus circumstantial bonuses, such as distance or barriers. Invisibility adds 20 if the target animate while moving a significant amount* or +40 if it is either inanimate or motionless. These bonuses are +10 and +20 for characters using telekinetic invisibility. When a character uses at least a move action to move while benefiting from cover or concealment, they can add their stealth check to the perception DC. The stealth check is penalized by 5 if the speed exceeds one-half of the character's movement speed (per move action spent). A successful perception pinpoints the creature, but line-of-sight and the ability bypass invisibility (if any) is still necessary to choose a target and ignore total concealment. This perception check is automatic and can occur once per round during combat or once outside of combat until the circumstances or nature of the actions taken are changed.

An invisible object cannot be chosen as a target for a spell or ability unless the object is touched. How this interacts with the activation time of the ability is unclear, but it is presumed that touching an inanimate, invisible object is free if the user is aware of its location. Visible material covering in or surrounding an invisible creature is sufficient for targeting that creature. Glitterdust specifically removes concealment from an affected invisible creature.

* What constitutes a significant amount is movement of the limbs or body position. Physical actions that require a move or standard action are significant. Retrieving or stowing an item is significant. Concentrating or directing a spell is insignificant. Insignificant is also moving fingers or rotating one's head and body enough to be aware of one's surroundings.