SharePoint 2010 page layouts versioning

A page layout deployed through visual studio feature automatically updates the underlying page layout file everytime a new deployment is done, however

1. This change is not reflected in version history, thus there is no way to figure out by just looking at the master pages gallery when was the page layout modified last time. The only way this can be verified is by opening the feature folder under 14 hive and making a note of the last modified date for the page layout file.
2. The page layout does allow us to manually upload a new version, but EnableSessionState attribute is not allowed in manually uploaded page
3. If a custom class derived from a PublishingLayoutPage class is used as base class for the page layout then manually uploaded page layout requires it to be registered as a safe control, even though the same template deployed through a feature does not.