Wall Heights

The wall height in our house design is 3.6m. One of the framing suppliers has suggested that their computer-design package can't be used for wall heights over 3m (and that we may need to engage a design engineer).  I have told them that there is a design procedure published for the Australian Timber Framing Code (AS1684) that outlines how to do the design for 3.6m walls. So we are a bit confused by the info from this truss & frame supplier. We will resolve this after they get the current working drawings.