|We put the FUN in Dysfunctional|
Architects want to put the diffusers precisely where they look the 'best' in his/her ceiling. The engineer wants the diffuser to be part of a complete system for his analysis and specification purposes, location is less of a concern. In a perfect world, the architect would place the diffuser and the engineer would copy/monitor it and swap it out for a more 'complete' version of it that meets his needs in his model.
Try doing that with families from 2 different categories.