Premiere does support native editing of AVCHD media from cameras. Not sure if that also applies to DVR media.
In either case, export will create a new render, even those segments that are left unedited. To get "smart rendering" where only edits are rerendered, you may need a third party add-on. In the past, MainConcept has offered this with the MPEGPro HD plug-in.
Thanks for the info on the MainConcept plugin. They too offer a demo which enabled me to determine that my footage could not be smart rendered (which is my main goal) 13 hours to render 5 minutes of cuts only footage is not really acceptable. Needless to say I'm disappointed. Thanks again.