HBP: a number of wrong numbers

[dorbandb]

>From the beginning there have been questions about JKR's ability with
numbers - most notably the number of students at Hogwarts, but there
have been other instances as well, IIR (no, I'm not going to look them
up - it's not really that important to this post...).  Now we've got
the issue of Hermione's O.W.L.s and how many she should have.  This
isn't something that stood out for me while I read, but obviously a
few others made note of it.  What did jump out at me during the first
read was the passage in the hospital wing, just after Ron drank the
poison mead:


"No more than six visitors at a time!" said Madam Pomfrey, hurrying
out of her office.
"Hagrid makes six," George pointed out.
"Oh...yes..." said Madam Pomfrey, who seemed to have been counting
Hagrid as several people due to his vastness.  To cover her confusion,
she hurried off to clear up his muddy footprints with her wand.


Is there something like a "mea culpa" from Herself in that passage -
acknowledging her occassional mishandling of numbers, hmmm?  That's
how I read it.  It made me smile.