[Stk] SKINI AfterTouch & ChannelPressure

[Carlos Pita]

Hi! I can't make sense of the following equalities
(left side taken from MIDI specification at
http://www.borg.com/~jglatt/tech/midispec.htm,
right side from SKINI.msg):

0xa0 (AfterTouch) == 160 == __SK_PolyPressure_
0xd0 (ChannelPressure) == 208 == __SK_AfterTouch_ == __SK_ChannelPressure_

Why are you treating AfterTouch (individual key pressure)
and ChannelPressure (average channel pressure) as the same
thing and mapping them to MIDI ChannelPressure? And
what do you mean by PolyPressure and why is it mapped
to AfterTouch?
Is the rationale that PolyPressure gives the individual
key pressure while AfterTouch aka ChannelPressure should
be considered per channel pressure? If it is this way,
I find it very confusing, as it not only renames MIDI
messages but also refers to a different thing than MIDI by
AfterTouch.
Then there is AfterTouch_Cont, that is, AfterTouch
seen as a control. What is the role of AfterTouch here:
x key or x channel? What is the point of having it
again as a control (I noted that instruments in the
stk distribution prefer AfterTouch_Cont control over
AfterTouch message) ?

Thank you in advance.
Regards,
Carlos