Proposed resolution:

Change [time.duration.nonmember] paragraphs 9 and 12:

template <class Rep1, class Period, class Rep2>
  duration<typename common_type<Rep1, Rep2>::type, Period>
  operator/(const duration<Rep1, Period>& d, const Rep2& s);

9 Returns: duration<CR(Rep1, Rep2), Period>(d) /= s.

template <class Rep1, class Period, class Rep2>
  duration<typename common_type<Rep1, Rep2>::type, Period>
  operator%(const duration<Rep1, Period>& d, const Rep2& s);

12 Returns: duration<CR(Rep1, Rep2), Period>(d) %= s.

[ 2009-12-24 Moved to Tentatively Ready after 5 positive votes on c++std-lib. ]

IMO CR alone is not really defined (it should be CR(Rep1, Rep2)).