What does current focus mean?
From the PrivateerPress forums: 


  FOCUS (in all caps) refers to the warcaster's FOCUS stat, which will only change if affected by an ability (Eg pDenny's feat). Focus (lower case) refers to the number of focus tokens.
  
  In the case of a spell, your magic attack roll is FOCUS + 2D6, using your caster's FOCUS 6.