Buildings Attached to non LEED-certified buildings

I am referring to the Supplemental Guidance to the MPR's; All Attached Buildings, 2) Treating Energy Systems. Our project is a horizontally attached office addition to an existing office / manufacturing plant. We have created our energy model with option a 'Separate Systems' as our mechanical systems are completely separate from those in the existing building and can be modeled separately. However, the addition and the existing building share service lines and meters for both gas and water. Further into the Supplemental Guidance Section III Buildings Attached to Non-LEED Certified Buildings, item 5 states 'Vertically Attached Buildings Only: Meters required to be separate’ Is the separate metering requirement in fact only applicable to the vertically attached buildings or is there a requirement elsewhere in this document that requires a horizontally attached building to have separate meters for the LEED-certified building and the non LEED-certified building? Thanks.