Perhaps I wasn't clear, or some are not assuming the same things about "differences."
For one thing, assuming that "merely semantic" are not really differences at all.
RAO 16-3 5)
a) the candidate stated that he had no differences; or
b) the court judged the stated difference(s) to be merely
semantic; or
c) the court judged the stated difference(s) to be more than
semantic, but “not out of accord with any fundamental of
our system of doctrine” (BCO 21-4); or
d) the court judged the stated difference(s) to be “out of
accord,” that is, “hostile to the system” or “strik[ing] at
the vitals of religion” (BCO 21-4).
This section of the RAO describes how the evaluation of the Presbytery must be categorized, for the record, of any differences with the Westminster Standards for a teaching elder. And now, with recent amendments,
the difference must also be stated in the candidates own words, too.
It's a high level of scrutiny, and rightly so, yet protecting the candidates right to evaluation of "scruples."
Of the four cases regarding "differences" with the standards, cases a), b) and c) may be admitted to the Presbytery, and d) may not. It has been astonishing to hear some argue that "d") cases can be admitted (another discussion for another thread).
I don't believe the PCA process intends a normal state of differences with the Westminster Standards by its would-be teaching elders (or any officer, ruling elder or deacon), but rather that being the exceptional case. It's not a mix-and-match system in a confessional system. Granted it's anecdotal, but I don't see most ruling elders and deacons stating differences, it seems to be about 50/50 with teaching elders....
Looking at it that way, we are dealing with "minor" v. "major" differences, something akin to the historic presbyterian system of scruples ("minor") vs. any other difference creating potential harm for the flock, to be protected by not admitting that man to office in the confessional system.
The point being, if someone is trying to come into the PCA to have authority, and with differences with the Westminster Standards, they ought do so with with great care, why they would have spiritual authority there, if they really don't agree, or don't believe what is confessed.
The oath is a very serious thing.