F9 bless questions

[konming]

After reading the manual and the forum, I understand that 6 AP is added only to standard weapons, not to extra weapons like hoof.

But I have some questions:
1) Is this 6 AP attack treated as a seperate attack, i.e. roll another attack roll? Or it just adds to original attack?
2) If it is added to original attack, then how is damage calculated? say someone does 13 damage (10 str+3 weapon) against an opponent of 20 protection. Will this be treated as 19 AP attack (therefore 19 vs 10) or will there be two seperate damage rolls, i.e. 13 vs 20 and 6 vs 10?
3) If it is treated as a seperate attack, will each attack lower defender DEF by 4?

Thanks for the answers.