Two Plot Problems

[rlevatter]

No: HPFGUIDX 187601

1. Sectumsempra:

When first used by Harry, inadvertently on Malfoy, Snape controls the damage easily with counterspells and tells Malfoy there will likely be no lasting damage with dittany applied.

Yet when the same spell is used by Snape, inadvertently hitting George, the damage (a severed ear) is  irreversible, because it was "dark magic".

Why was it irreversible dark magic when Snape, a member of Order of the Phoenix, does it but not when Harry does it?

2. Trelawney:

In The Seer Revealed chapter in Half-Blood Prince, Professor Trelawney recounts to Harry her recollections of meeting with Dumbledore for a job interview 17 years earlier. Harry realizes she is telling about her divining for Dumbledore Harry's birth and the challenge to Voldemort. And Harry is shocked when Trelawney reveals that the Voldemort spy was none other than Professor Snape.

Here's the problem. Trelawney can't remember what's happening when she's actually giving a divination. That is evident in this very scene (she doesn't remember telling Dumbledore about Voldemort) and evident in book 4 when she divines for Harry that Wormtail will soon seek to restore his master.

And it is a key part of the plot that Snape was found and sent away before Trelawney finished the entire divination. He heard only the first part.

So the question is, if Snape was sent away after Trelawney began but before Trelawney finished her divination to Dumbledore, how did she know about Snape? Did she give the first part, wake up, see Snape sent away, then go under again and give the second part? Obviously not.

So how would you explain this?

rlevatter