Expert Assistance
If you have 5 or more ranks in a skill you’re using to aid another, you can grant a higher bonus. For every 10 points your check result exceeds 10, the circumstance bonus increases by 1. To determine the circumstance bonus quickly, simply divide the helper’s check result by 10, round down, and add 1.
At the DM’s option, this rule can also be extended to using the aid another action in combat to improve an ally’s attack roll or AC. Any character who has a base attack bonus of +5 or higher can grant a greater bonus on an ally’s attack roll or AC as described above.