Please follow up with mark@flux.ai . Exporting pick and place with flux provides the component centers relative to the 0,0 origin. However, I believe centroids need to be referenced to the bottom left of the PCB. I am going to try to fix this manually in excel and see if that is the manufacturing blocker. Otherwise, look at this PCBWay reference: https://www.pcbway.com/helpcenter/technical_support/Generate_Position_File_in_Kicad.html