Masterwork Darkwood shield cost

[JBGamer2300]

Greetings Paizoites, I apologize in advance if this is somehow a stupid question, or if it has been answered elsewhere and I just didn't find it.

Essentially my problem is this: I want to buy a masterwork heavy wooden darkwood shield, but I find the exact wording about the cost of darkwood in my corebook pretty ambiguous. It's only 3rd printing so if they changed the wording please let me know. The bit that has me confused is this:

"To determine the price of a darkwood item, use the original weight but add 10 gp per pound to the price of a masterwork version of that item."

This suggests to me that darkwood items cost the same as a non-darkwood masterwork item with the addition of the 10gp per pound. However, the way this is phrased does not seem to explicitly say that darkwood items are automatically masterwork items. Therefore, my conclusion is that in order to make a masterwork version of a darkwood item, I will essentially have to pay the masterwork cost twice. Meaning the actual cost for, say, a masterwork darkwood heavy wooden shield would be 150gp (masterwork cost) + 150gp (darkwood cost) + 100gp (weight cost) +7gp (basic item cost) for a grand total of 407gp.

Am I totally out of my mind here and about to stiff myself 150gp, or is this actually how it works?

[mplindustries]

I'm pretty sure a darkwood shield would cost you 257gp, and it would have to be masterwork.

[SlimGauge]

Figure the cost of a masterwork regular materials version of what you want. What does it weigh ? Multiply that weight by 10 gp. Add the result to the first cost you calculated. That's what you pay for the masterwork Darkwood version.

[Ciaran Barnes]

Mine cost 257 gp.

[Troubleshooter]

Pathfinder Core Rulebook, page 467.

Darkwood Shield
Aura no aura (nonmagical); CL—
Slot shield; Price 257 gp; Weight 5 lbs.
DESCRIPTION
This nonmagical heavy wooden shield is made out of darkwood. It
has no enhancement bonus, but its construction material makes it
lighter than a normal wooden shield. It has no armor check penalty.

The price breakdown is:
150 gp (masterwork)
007 gp (heavy wooden shield)
100 gp (10 pounds, at 10gp per pound)