Trial Adoption runs significantly faster than the adoption process. This is counter intuitive as Trial Adoption is just full adoption plus a rollback?
Trial Adoption just creates a report but does not do an Adoption with database Rollback. This is why there is a large difference in executions times. It is the Trial Migration (not Adoption) that does a Migration with database Rollback. So, Trial Adoption is a reporting tool and Trial Migration is a Migration w/Rollback.
The Adoption "unadopt" phase is doing some cleanup of business/system objects. It is process intensive and cannot be avoided or turned off.