Data Center Baseline HVAC System with Ancillary Office Spaces

Hi Marcus Your comments and Suggestions were valuable for my understanding on doing my LEED EM for Data Center. I would like to confirm on my understanding. I have a 7 storey building of which 5 floors are data center, 2 floors are ancillary office spaces. Total GFA of DC alone is 25,000 Sqm while the office/other spaces account to 10,000 Sqm. So can I say since since my primary function of my building is DC I cannot use the exception under G3.1.1 to use System 3 or 4 for DC space. Rather should use System 7 or 8 for the DC spaces while the exception would be applied for the normal office spaces which would be modeled with System 3 or 4 as their operating hours and loads differ significantly from the DC. Please advise.