Very very basic Power Advantage question

[devlin1]

I feel like an idiot for asking this, but....

A character has 15 STR, and has an OAF 1d6 HKA. How much does Armor Piercing (+1/2) for that HKA cost? It seems to me that cost should be calculated based on 30 points: 15 from STR, and 15 from the HKA. However, I almost always see this power bought just as:

1d6 HKA, Armor Piercing (+1/2), OAF: Sword (-1). Active Point Cost: 22, Real Cost: 11

However, by my logic, it ought to be:

1d6 HKA, OAF: Sword (-1) plus Naked Modifier, Armor Piercing on 30 Active Points, OAF: Sword (-1). Active Point Cost: 30, Real Cost: 15

I feel like I'm greatly overcomplicating what has seemed for years to be a simple matter. :(

[Steve Long]

The cost is calculated based only on the HKA -- the STR used or added doesn't factor in, because it can vary. However, when applying STR to an Advantaged attack, you have to pro-rate it, as described on 5E 272.