Support 2nd round of Pre-processing will be convenient.
Because if we use Convert Item then Pre-processing, it shows costing result.
But we made mistake at the Convert Item, we need to create a job again from scratch. Otherwise not reflected even we push back job to Convert Item and made changes.
Now a day integration to ManTra is increased. Sometime, hardly to ask client to re-create job.
Believe, if "Pre-processing" could clean up DB and files that previous Pre-processing generated, the issue will be solved.