Building Reuse of a previous LEED buiilding on same site

I have a question regarding compliance with this credit as long as MR Credit 1.2. Would this credit apply to a situation in which we are renovating (i.e. finishing an extension) an existing building that was built as part of the same project a few years earlier, which has been applied for LEED credit. All buildings onsite were built part of the project (no buildings were onsite prior to the project). This specific project now is the completion (i.e. build out) of the original building built five years ago which has already been submitted for LEED certification. The full envelope of the building was built and completed years ago. This project will maintain the existing building envelope and will essentially just be completing/extending indoor build out and systems (HVAC, electrical, fire, etc.). Does it make sense to attempt to apply for MR Credits 1.1 and 1.2. OR would it make more sense to include this project as part of the original project for LEED certification. This would obviously require that we pull back our previous submissions, modify appropriately and resubmit. Not sure if this matters, but there are other buildings onsite that are also seeking LEED certification and we are using the Master Site Campus approach. Any help or feedback would be greatly appreciated.