I am working on a LEED v.4 C&S office project, but since a PI forum section for it has not been set up on LEEDuser yet, I thought I'd post here.

The project is located in Europe. The exact occupancy of the building is not known, so the reference manual says that I can either use default occupant density from ASHRAE 62.1-2010, Table 6-1 (1 person per 20sqm of net area) or Appendix 2 Default Occupancy Counts (1 person per 23 sqm of gross area). At the same time, the HVAC and electrical systems have been designed by the project engineers to accommodate the peak density of 1 person per 6sqm, which is a local code maximum density. But this by no means implies that future tenants will indeed put such a high number of people in the building.

So, my question is:  which one of these occupant densities should I use to calculate the FTE's for all the LEED credits and which occupant density should go into the energy model?

I would like to use LEED default counts as this will make credit compliance easier. But I want to make sure that this is a valid approach in light of the above information.

To add to the confusion, I can't use the Appendix 2 Default Occupancy Counts for the ventilation rate calculations because I need to indicate net areas for all zones (and ASHRAE 62.1-2010 uses net areas), while the LEED default count is based on the building's gross area. 

Any advice would be greatly appreciated!