There appears to be a bug in editing Sharepoint 2010 Organization Profiles. If you try to edit the Profile SubType without editing any other field your change is not saved. The work around is to update any other field at the same time (and then don’t forget to change that field back).
Refer to the comments on MSDN http://msdn.microsoft.com/en-us/library/ms545122.aspx for an example on how to do this in code.