We have a NCv2.2 certified building that is now constructing an addition. This addition was planned years ago and was registered as an NCv2.2 project but was then put on hold. The project has come back to life and we are having trouble deciding how to best proceed and with which rating system. The addition is connected to and will be sharing the mechanical system of the original building. Because they share mechanical systems, the ability to draw a clear LEED boundary is very challenging. Our understanding is that v2.2 projects don't need to follow the new MPRs required for v2009 projects. Does anyone have experience with this kind of situation and how the USGBC will view this project? We are working with our mechanical engineers to confirm that an energy model can be done in a way that separates the addition from the existing. Is that the only credit we need to be concerned about? Any help is greatly appreciated!