THE RULES REGARDING THESIS CREDIT REQUIREMENTS AND PRELIMS:

The grad school lists the requirements in the grad school rules
document on their website, (which isn't easy to find).  The link is
http://www.colorado.edu/GraduateSchool/policies/_docs/GraduateSchoolRules.pdf.
The operative language is copied below.

Basically, a student can count up to 10 credits before proposing, max
of 10 credits during the semester they propose, and must sign up for 5
credit each semester post comp.

Students can take dissertation hours prior to completing their area
exam, there is no requirement stating they must have completed the
Area exam first.

____________________________________________________________

Doctoral Dissertation Credit Hour Requirements

To complete the requirements for the Ph.D. a student must register for
a minimum of 30 dissertation credit hours. Distribution of those hours
is as follows:

-a student may not register for more than 10 dissertation credit hours
in any one semester, including summer

-not more than 10 credit hours taken in semesters prior to the
semester in which the comprehensive examination is passed may be
counted in the 30 dissertation hours required for the degree

-not more than 10 dissertation hours of credit taken the semester in
which the comprehensive examination is passed may be included in the
30 credit hours required for the degree