After upgrading from AirWave 8.4.1 to 8.6.1, VisualRF became seriously confused about feet and meters. Firstly, all existing floorplans had their metric distance values divided by 0.3048. Measurements still show as meters, and RF calculations seem to be correct, but the values are in feet.
Adding new floorplans is doubly screwed. If I measure a floorplan at 10 meters, it shows 10 meters during the process, but goes down to 3.15 meters after saving - which in practice is 3.15 feet. Ceiling height more or less follows the same pattern, although not consistently.
While I can probably remember to multiply all new floorplans by 10.764 from now on, it caused some expensive mistakes before I figured it out, and I'd assume other non-US customers will find it out the hard way, if at all.