Hi All
In the MKW2xDxxx reference manual (Rev. 1 Nov. 2013) the following is found:

In section 4.4.2

But

Therefore it looks like there is an error in the section 4.3.1.2 stating PTA18 rather than PTC0.
If a true error, it could be fed back to the documentation team for correction in a future edition.
Regards
Mark