I have a Python script for P5, used to set the distance for the focus option in Firefly, which uses a value of 8.85 feet to one Poser Unit. This is 106.2 inches. Dr. Geep uses the simple-to-calculate 100 inch value. Some versions of Poser are believed to have used the simple 96 inch value. If the strange Imperial meadurements came to some nice round figure in metres, it'd make sense, but they don't.