Alison -- very sorry for the confusion, and you should consider all the specs directly under http://www.loc.gov/z3950/agency/zing/zing.html to be out-of-date. We had a two-day meeting last week and settled most of these issues.
There will be a new directory,
http://www.loc.gov/z3950/agency/zing/srwu/
and we'll migrate the updated specs there, as quickly as possible, but it's a cumbersome process and may take a couple weeks.

Meanwhile, one addition to earlier responses:

> Moving on to response parameters, the draft specification lists queryStatus and resultSetStatus.

There won't be any status parameters.  We've concluded that they aren't needed.

--Ray