S-TEC 60-2 audio warning

I'm confused. I've spent many years flying a Mooney with a KFC200 autopilot
that has an audible disconnect warning. We now have a Twin Comanche in
which we installed an STEC 60-2 a couple of years ago.

Recently, testing the 60-2 pre-flight, I noticed that there was no audio
warning when the autopilot was disconnected, whereas there *is* an audio
warning when e.g. the trim lights illuminate. Without much further thought,
I flagged this as an issue with our maintenenace organisation. They say, and
I have confirmed, that the POH supplement says that RDY light flashes for 5
seconds on disconnect, but it doesn't mention an audio warning in such
circumstances.

So, did I misremember (imagine?) that an audio warning used to sound when
the a/p was disengaged? If so, why would someone make an a/p with an audio
warning built-in which doesn't sound for the most obvious message ("your
airplane!")?

Julian Scarfe