[RPG] Flurry of Blows calculation

Yes, as per Player's Handbook FAQ

Found reference here:

Attack powers that have a target line and deal damage are attacks (See: Magic Missile). Ergo, Flurry of Blows is an attack.

This is clarified in the FAQ for Player's Handbook, in case anyone was wondering where it's coming from.

And the relevant original text is here (item 38):

1. What happens if I use magic missile while benefiting from a power like greater invisibility? Does it count as an attack and would my invisibility end?

Yes, it does, and yes, it would. The initial use of any attack power that has a target line, an attack line, or both counts as making an attack. Because of this fact, using an attack power like the fighter's rain of steel does not count as making an attack, since the power has neither a target line nor an attack line

The formula for a melee attack roll is usually:

BAB + Str Mod + 1d20

Flurry of Blows makes two changes to this formula:

When doing so, he may make one additional attack, taking a –2 penalty on all of his attack rolls, as if using the Two-Weapon Fighting feat. These attacks can be any combination of unarmed strikes and attacks with a monk special weapon (he does not need to use two weapons to utilize this ability).

And

For the purpose of these attacks, the monk's base attack bonus from his monk class levels is equal to his monk level.

This makes the attack formula:

Monk Level + Str Mod - 2 + 1d20

The class table combines Monk Level and the -2 penalty into the column Flurry of Blows Attack Bonus. Giving you the formula:

Flurry of Blows Attack Bonus + Str Mod + 1d20