Class size discrepancy (and JKR's phone)

[justcarol67]

pippin_999 said:
> :sings, to the tune of Eleanor Rigby: All the DADA students,
> where did they all come from?

Dina responded: 
> By magic, of course.
> 
> Granted, 'hands-on/practical' classes like flying and Herbology
might have to be 'staggered' (professor choice on class size and/or
monitoring of supplies) while elective classes like CoMC and
Divinations would not require all students for a year to attend,
however, that DADA count seems too high for a single year/single
house.  IIRC, unlike the movies, Gryffindors don't share their DADA
class with any other house. <snip>

Carol adds:
You're right, they, don't--unless the policy changed in Harry's fifth
year. But the only students who speak up in Umbridges are the
Gryffindors we've always known--Hermione, Harry, Dean, and Parvati. So
how did we get from ten Gryffindors in Lupin's DADA class in PoA to
thirty in Umbridges? Is JKR trying to "fudge" the numbers to make the
number of students add up to 1000?

Carol