Emu XL-7 & MP-7 User's Group

I have read the section on "Assigning Tracks to MIDI Channels" 3 
times.  Since I just
started learning MIDI, I am still not sure what is the purpose of 
assigning certain tracks to
different Channels other than the default Channels assigned by EMU.  

Anyways, I go in and tweek with assigning channel parameters:
Scenario: track 9 has a preset of 'wah guitar' with sound pattern of 
lets say 'tom dick 
harry' and is assigned to Channel "C09A" by EMU's default, while 
track 1 has a preset of 
'kick bass'with sound pattern of lets say 'M N O P' and is assigned 
to Channel "C01A' by 
default.  Now, if I hit pattern in the edit mode and reassign track 9 
to Channel 'C01A' and 
hit pattern again to exit out and press the play button with track 
9's LED button lit it 
plays sound pattern of 'tom dick harry' but with snare voice (not 
kick bass).  If anything,
shouldn't it play pattern of 'tom dick harry' with kick bass as 
voice?  And when I do the 
reverse (assigning track 1 to channel 'C09A') the pattern 'M N O P' 
is played with the 'wah
guitar' voice (expected) but it seems like it is playing in a 
different note/pitch.  

Sorry for the lack of appropriate 'electronica' terminology and the 
long examples.  Any help
is really appreciated.