How does a Monk benefit from the Power Attack feat when flurrying with a quarterstaff?

Question

A Character with the Power Attack feat can decide to use a quarterstaff as a two-handed weapon and apply 1.5 × Strength bonus to the damage roll, plus double the number he decided to subtract from the attack roll.

Now a Monk that decides to use Flurry of Blows with the same weapon must follow the ruling in the Player's Handbook (41):

When using weapons as part of a flurry of blows, a monk applies her Strength bonus (not Str bonus × 1-1/2 or × 1/2) to her damage rolls for all successful attacks, whether she wields a weapon in one or both hands. [...]
In the case of the quarterstaff, each end counts as a separate weapon for the purpose of using the flurry of blows ability. Even though the quarterstaff requires two hands to use, a monk may still intersperse unarmed strikes with quarterstaff strikes, assuming that she has enough attacks in her flurry of blows routine to do so.

The quarterstaff, despite being a two-handed weapon, is treated as two separate weapons in this context but it still requires both hands to be used.

That wouldn't be much of a concern per se, but what if the Monk decides to use the feat Power Attack with the above class feature? How should the quarterstaff be treated in this case?

1. As a Two-Handed weapon. Power Attack doubles its bonus.
2. As a Double weapon. The Power Attack bonus is not applied to the light end of the weapon.
3. As two One-Handed weapons (e.g. two clubs). Power Attack affects both ends but its bonus is not doubled.

Or how is it generally ruled?

Answer 1

TL;DR: I would rule towards the 2 One-Handed Weapons case.

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The description of Flurry of Blows leaves us a bit in the dark. Specifically, it mentions:

In the case of the quarterstaff, each end counts as a separate weapon for the purpose of using the flurry of blows ability.

But does not specify how said ends are wielded.

It would seem logical to fallback to the wielding methods assigned by the normal usage of a Quarterstaff. It can be used as either a Two-Handed Weapon OR a Double Weapon, and is clearly being used as a Double Weapon here -- striking with both ends -- therefore one end is One-Handed wielded by the Main Hand and the other is Light wielded by the Off Hand.

However, there is normally a link between Wielding and Strength Bonus:

• Wielded with 2 hands: + 1½ Strength Bonus.
• Wielded with Main Hand: + Strength Bonus.
• Wielded with Off Hand: + ½ Strength Bonus.

And Flurry of Blows starts by:

When using weapons as part of a flurry of blows, a monk applies her Strength bonus (not Str bonus ×1½ or ×½) to her damage rolls for all successful attacks, whether she wields a weapon in one or both hands.

Since both ends of the Quarterstaff therefore receive the regular Strength Bonus as if wielded by the Main Hand, I would therefore argue both ends should each be treated as a One-Handed Weapon wielded by the Main Hand for the purpose of Power Attack.

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As an aside: the poor Monk needs all the help they can get, Flurry of Blows is hard to use, and Power Attack is tough on a Monk with their low BAB. Let's avoid the more crippling ruling of "Double Weapon".