Alesis Andromeda A6

Hi Folks,

when I record the midi of A6 in mix mode using a custome made mix 
preset and Logic, I get 16 stacked notes by pressing a key once!!!!!But 
my A6's Arp and Seq works normally.
On the other hand, when I record using the A6's factory multitimbral 
mix preset, then I don't get those stacked midi notes, but my A6's Arp 
and Seq won't work anymore.

Can someone help me out to set up the A6 the way that I won't get  the 
recorded stacked notes, while I could use the Arp/Seq?

thanks

Kamy