Historic tuning modes

[Gerald Posey]

As a new guy having only tuned three pianos using Tunelab I have some
questions.  I was intrigued by the idea of HT's helping a specific piano and
I read the good things about
Werckmeister III .  Thinking, "Why not?", I loaded it and tried it.  First
of all I was surprised how well in tune this beat up old piano is, and
second, it seemed like it was already in Werckmeister .  I barely had to
touch the pins.  Is it just that HT's are only slightly different or
coincidence?
Gerald