[CSS3-content] Implied counter-increment

So far in CSS3 I've come across two implied counters:
   pages     (CSS3 Paged Media)
   list-item (CSS3 Lists)

The 'pages' counter is incremented on each page box, as if
   @page { counter-increment: pages; }
were implied.

The 'list-item' counter is incremented on each list-item, as if
   :select-all-elements-with-display-list-item { counter-increment: list-item; }
were implied.

My question is, what is the specified value of counter-increment on
these boxes? If I specify "counter-increment: mycounter;" does the
implied counter stop incrementing?

Also, do we need to add a 'normal' or 'auto' value to counter-increment
so that we can distinguish between
   counter-increment: none; /* doesn't increment implied counters */
and
   counter-increment: normal; /* only increments any implied counters */
?

~fantasai