Re : Upgrading Client from 3.5.3 -> 3.6.2 results in numerous unwanted changes for updateToTag

I think what you are seeing is just liquibase updating the checksums for all of your changesets - the checksumming algorithm changed somewhat recently (I don't recall the exact version number, but it was 3.6.x IIRC). So it won't re-apply those changes to your schema, but it does need to update the checksum that is stored in the DATABASECHANGELOG table. 

Steve Donie
Principal Software Engineer
Datical, Inc. http://www.datical.com/