Changing DX Aging Criteria

We are getting ready to archive data based on 'date last modified' using DX 6.2 SP1 but would like to change this in the future to archive based on 'date last accessed'. We currently cannot use the latter option due to SAV scans changing that attribute when we run a weekly scan on our file servers. Does anyone have any experience with having made a change like this in the past and if so do you any problems or warnings that you would like to share? Or if know if there is a good document describing the process?

The Administrators Guide discusses the various options but nothing in detail on making a change like this. My assumption is that if we were to make the change in the move rule on the next scheduled scan, real times moves is disabled, then data that was archived based on 'date last modified' but no longer qualified to be archive based on 'date last accessed' would be fetched back from the Centera to the extended drive and data that matched the new criteria would be moved but I would like to have a better understanding before proceeding with the original purge of the data.

Thanks