EXS 24 Logic Sampler Users Group

Hi all,
Does any one know why certain EXS instruments would seemingly eat 
polyphony.  I have a GOS violin instrument that when 1 note is played 
it uses 4 notes of polyphony.  It is a keyswitched patch with 4 layers. 
  It is as though it is using all 4 layers even though only 1 is heard.  
I understand that if there is xfading more voices would be used than 
notes played.  But there is no xfading.  Any ideas?

Julie