In this scenario, a new strategy must be created, each time the content of the DDLIN input file is changed.
If the requirement is to regularly compare the input file to a subsystem(s), after amending the content of the input file, then we would recommend using the Batch Compare Facility. This will create a new strategy (replacing the old) each time it is executed, comparing the latest input DDLFILE to your subsystem.
We can compare the source DDLFILE to either a target subsystem, or to a target DDLFILE.
So one approach could be to create a DDLFILE for the production subsystem and a DDLFILE for the test subsystem. The Batch Compare Facility can then be used to create an Automap compare strategy, comparing these two files. Analysis can then be performed against this new strategy.