I have looked into rounding in Autodesk Architectural Desktop's Property Data Formats a little further. One quick note first, the property showing the rounding technique mentioned in my previous blog post is the Occupants property in the OccupantLoadStyles Property Set Definition. I should have included that in the previous post.
Rounding up and rounding down also do not work in ADT 2004. I took some time at lunch today to set up a sample file that demonstrates this, and attached it to a new reply in the same thread that has the occupant calculation sample. The post there describes the sample file in detail; a schedule table in the file shows the effect [or lack thereof] of selecting Up, Down or Nearest for the rounding method in a Property Data Format. There is also a property that demonstrates the use of the VBScript Round function, which allows you to round a real number to a specified number of decimal places - nearest only, and "5" rounds up for odd numbers and down for even numbers.