Relationship between change type and profile type

Iam curious to find out the relationship between these two in an ECR/CM.

In CM,the changetype is 0 but still there is an option to select profile type-wonder why.

Also,normally we select the profile type in accordance with change type.

What would happen if I select change type 104 and profile type say Z_107.

similarly,how would it affect my CM if I select profile type say Z_108 ,instead of z_ecm.

Thanks ,

DJ