Ahhhhhhh ok .. I've missed the weapon enhancement via arcane pool .. Tnx Frodo ..
so Lev3 Guide is correct
Lev6 still miss something .. BAB +4, DEX +4, Weapon Focus +1, +1 Weapon = 10 = Basic Attack .. with 1 arcane pool I add a +2 enhancement to my scimitar (that stacks with the +1 already on the weapon) .. after I use another arcane pool to make the scimitar keen .. and finally I use another point to start Arcane Accuracy (+3 to hit) .. so Basic Attack +10, enhanced weapon +2, AA +3 = +15 .. with combat spell +13/+13 ..