What about commissioning / balancing the system(s)?
Typically a Fabric Ducting system is designed to match the volume and pressure of the AHU system. It’s designed to deliver a certain volume of air for each branch which has been designed and calculated as part of the overall system design. Assuming no branches to other systems or non fabric diffusers exist within the system then the fabric ducting system will self balance. If there are other types of diffusers (Grilles for example) you will need to install dampers to control the air volume to the separate parts of the system.