Needs to clarify the iCloud mechanism

Needs to clarify the iCloud mechanism

I need to clarify my understanding of how iCloud should work and am
following a tutorial to get my hands on it. To be precise here is what I
am reading now:
http://www.raywenderlich.com/12816/icloud-and-uidocument-beyond-the-basics-part-3
I build the example given as I move on with the reading.
And I just finished everything until the "Fixing Deleting" paragraph, not
including it.
Stopping the reading, I took a break to run the app on two devices and see
how it behaves.
Here is what surprised me (in fact the reason for this post):
I noticed that on each device I find myself with two independent sets of
data that I can access: One when "Use iCloud" is OFF and another one when
"Use iCloud" is ON. The set accessible when "Use iCloud" is OFF is
particular to one device. The set accessible when "Use iCloud" is ON is
synchronized between the two devices.
My question is: Is this the way it should be?
If the answer is NO, then I probably did something wrong when building the
example.
On the other hand if the answer is YES, then it is working fine. But it is
not exactly what I expected when I started.
I thought there should be a synchronisation between the two sets of data:
set accessible when "Use iCloud" is OFF and set accessible when "Use
iCloud" is ON.
Any bit of explanation from someone who has some experience with iCloud
would certainly help me clarify the subject in my mind. Thanks for any
useful tip.