Ogrork the Mighty
Explorer
Can you use both of these during the same turn? For example, can you pull 5 for Power Attack and pull an additional 5 for Combat Expertise on your same turn?
Why do you ask though? I can't really think of a use for such an action.
If you have combat expertise & power attack, that probably suggests you are a big fighter type. If you are not able to hit the creature and resulting to this tactic just on the off chance you get a 20 I recommend another tactic . . . Run Away.