Conflit with 2 subscription

I made 2 subscription with different level.

Example:

Subscription 1 with x level and z menu
x level was done using only positive rule, I selected the menu items I needed and I unchecked the menu items I did not need to this subscription

Subscription 2 with y level and z menu
y level was done using only positive rule, I selected the menu items I needed and I unchecked the menu items I did not need to this subscription

Now when you sign up for only subscription there is no problem, In fact, the menu items can be seen properly, but when you sign up for both subscriptions, you can only see the menu items in common and the rest of the menu items there aren't visible.

WHY?? Solutions?
Thanks for all!