It's very important to note that with multiwinner approval voting, merely counting the votes per candidate and picking the top ones can lead to rather unfair results
(unlike in the single winner case).
For instance, if we elect k=3 candidates out of 6, say, $a,b,c,d,e,f$, and out of N=19 people, 10 vote for $a,b,c$, and 9 - for $d,e,f$, then, with approval voting, $a,b,c$ get elected (as $a,b,c$, get 10 votes each, more than $d,e,f$), and almost half the voters, 9 out of 10, get no representation of their views.
This is obviously bad - in such a case a fair outcome would be something like $a,b,d$. Here "fair" has to be quantified, of course.
I've posted some details (and pointed at some solutions) on this here:
It would be interesting to get the anonymised returned ballots and see if we did well on this occasion.
As well, adjustments ought to be made along the lines outlined above.
Dima