See below for info from ASHRAE on a proposed addendum to Standard 90.1-2010.
The Appendix G baseline envelope, equipment efficiencies etc. would be frozen at 90.1-2004 values. This has obvious implications for LEED energy modeling and other Appendix G analyses.
Additionally, Appendix G can be used as a compliance path, so there would be no need to do both a PRM and ECB model for the same project.
The review period for this addendum lasts until November 26th.

The proposed addendum is here:
https://osr.ashrae.org/sitepages/showdoc2.aspx/ListName/Public%20Review%20Draft%20Standards/ItemID/806/IsAttachment/N/90.1BMFirstPPR.pdf
The public review page is here:
https://osr.ashrae.org/default.aspx