Assuming you have the S-26 trimmed for a given speed when the power is
pulled at some point it will stabilize at the ....

Well, your comment is correct only when the diving S-26 stability is in
the envelope. If its current stability is out of the envelope, it may
never reach its former trimed speed (or stable state). If you've
readed the basic air dynamic in the ATP or commercial exam materials,
you know there are 2 basic stabilities of an aircraft...dynamic and
static stability. These 2 factors (and others) determine the
performance envelope of an aircraft. If the air dynamic is that
simple, all my friends in JPL and Boeing will be out of jobs by now.

Why the most popular aircraft such as 182 (epscially most high-wings)
will fall to its trim speed when power is lost because its stability
envelope is large. So when power factor changed, in most of cases, its
static stability will let the aircraft fall back into its balance
state. Not all the aircrafts like this, you can proove it by common
sense. (think about other types and models, jets, B2 bumber...etc.)