Hi Michael & Ryan,

I think I found the key to getting the sub account to change using the courses csv import‌. The key to getting the course to move sub accounts‌ for me was to us the SIS ID associated with the sub account and not the ID.  If you have done UI changes already to this course you may need to use the #override ui changes‌ option when importing the

#csv file‌.

Hope this helps. 

Example of how I have the data in the csv‌ below.

Course settings before:

Course settings after: