Question about multiplying damage with decisive strike [duplicate]

Question

So, reading another question about Decisive Strike, the answer was that it works the same as a critical, by multiplying its damage and therefore utilising multiple rolls and adding the totals, however, it's still not fully clear to me.

Let's say that in this instance a Monk 4/Swordsage 2 with Assassin's Stance, Fiery Fist and Shadow Blade (let's say the DEX bonus is +4) makes a decisive strike sneak attack unarmed on a monster.

Normal damage would be 1d8 via unarmed damage + 1d6 fire damage via Fiery Fist + 2d6 per sneak attack + 4 via DEX bonus

I know the example is convoluted but i helps me know which sources multiply and which don't. As I understand, with decisive strike it would be the following:

2d8 via unarmed damage + 2d6 fire damage via Fiery Fist + 4d6 via sneak attack + 4 DEX bonus

Is this correct? Is the fixed bonus also multiplied (in this case the +4 damage for DEX)?

And also, one little question on decisive strike; it says that every other attack before the start of my next turn is also doubled, yet the penalty only applies to the first roll. Does this mean that any other attack I get to make this round (by, let's say, Fire Riposte, or an AoO), also gets double damage without penalty?

Sorry for the convoluted question, but when I start reading supplementary manuals, even if they are the PHB2, things get more and more confusing. Thanks in advance!

Answer 1

Multiply your base damage and any flat bonus damage. Do not multiply bonus damage dice.

From the SRD's section on combat statistics:

Multiplying Damage

Sometimes you multiply damage by some factor, such as on a critical hit. Roll the damage (with all modifiers) multiple times and total the results. Note: When you multiply damage more than once, each multiplier works off the original, unmultiplied damage.

Exception: Extra damage dice over and above a weapon’s normal damage are never multiplied.

So for the damage factors in your example:

• 1d8 via unarmed damage: Roll this twice, this is your base damage
• 1d6 fire damage via Fiery Fist: Don't multiply this, it's a bonus damage die
• 2d6 per sneak attack: Don't multiply these, they're bonus damage dice
• 4 DEX bonus: Multiply this, it's a flat damage bonus, not a bonus damage die

Thus, your final damage in your example would end up as:

2d8 (2 * base) + 1d6 fire (Fiery Fist) + 2d6 (sneak attack) + 8 (2 * dex bonus)

And also, one little question on decisive strike; it says that every other attack before the start of my next turn is also doubled, yet the penalty only applies to the first roll. Does this mean that any other attack I get to make this round (by, let's say, Fire Riposte, or an AoO), also gets double damage without penalty?

That's correct. The attack penalty specifically says it applies to "this attack roll," but the damage multiplier applies to "any other attack you make before the start of your next turn."