[Overtaxed]

BUT, when Eowyn and Merry are injured he calls for kingsfoil (and perhaps uses it for Faramir too?). Is that an "oops" in the movie? Or is there a subtle difference I'm just missing.

Not really an oops! Aragorn goes off to collect athelas for Frodo when he's stabbed by the Morgul blade. He puts them in hot water and bathes Frodo's shoulder with it. When Eowyn and Merry are injured, he asks Ioreth for athelas but she doesn't recognize the name. "Kingsfoil" is the common name for athelas.

[Corin Stormhands]

Aragorn goes off to collect athelas for Frodo when he's stabbed by the Morgul blade. He puts them in hot water and bathes Frodo's shoulder with it. When Eowyn and Merry are injured, he asks Ioreth for athelas but she doesn't recognize the name.

Jen kinda cleared it up with the different kind of wound thing. It just threw me when in the movie he said "this is beyond my powers of healing..."

On a side note, do we know yet who plays Ioreth? She's gonna be interesting...