SIS Questions

<p>I successfully made an enrollment request page, but there are some confusing things on it. The Biology 2010 lecture course I want lists the times as:
MoWeFr 11:00AM - 11:50AM
MoWeFr 11:00AM - 11:50AM
Fr 3:00PM - 5:00PM
What does this mean?<br>
I am already enrolled in Econ 2010, but I want to change my discussion time. SIS makes you put both the class and discussion into your enrollment requests as far as I can tell. You have to select the two classes as a group to enroll into. When I try to enroll later am I going to lose my spot in my Econ 2010 lecture? I am assuming you have to drop a class before you can add the same one to your schedule.
Hopefully this all makes sense.</p>