Discrepancies using Point Clouds in Revit Architecture

Anybody using Point clouds with Revit Architecture and getting mixed/erratic results? three different users using the same point cloud have come up with three different building lengths after extracting the walls. Same method was used, but in each case the building ends up being a different length, window spacing is off and different between the three models. We are using the Point Cloud extraction tools from Autodesk Labs. How can we make sure that the Point cloud comes in at the same scale, true to actual measurements on each machine? Anybody having this same problem?