EXS 24 Logic Sampler Users Group

Saw all the posts and zipped over to the site to download. Awesome sounds. I 
now have to go back to every song i have and replace all horn sect. with sams 
trumpet. (This says something about the state of my library, Saving my 
pennies for VSL.... I wish I had that many pennies! ;-)

Anyway, being brand new to logic and the exs something is confusing me.
I opened up the exs editor to take a peak at the sample layout... Wow! My 
biggest patch has maybe a quarter as many zones. I counted 16 layers before 
my eyes went blurry.  My question ( concern) is what are they all for? I 
dragged the top two over to the right in order to fill out my keyboard (Midiman 
Keystation) and I was getting Identical sounds as the keys depressed where 
the full zones were....soo.. the 14 other layers are doing...?

 I'm guessing varying expressions and phrasings? If so, great! Unfortunately, I 
don't know how to access them. As I said, still getting my feet wet and when 
you guys talk about Velocity layers and midi controller numbers I just go 
numb. Oh, I know I'll get it, but if one (or more!) of you can jump start this 
phase of my education I would greatly appriciate it.. 
I have noticed some posts referring to a lack of  control info with a giga import. 
Is this a prob with my scenario?

One last question, When the exs does the import it converts the doc into an 
aiff sample right? Can I then delete the original to free up some drive space?

Love the forum

Christian