development of copper

I have been revisiting the announcement regarding MG14 and Windabout re:

"A review of the PFS document by engineering group Sedgman Metals has concluded that
the PFS could be brought to bankable status in 15 months if the regulatory approvals
process was initiated at the same time as the rest of the BFS."

Has anyone any experience as to why it would take another 15 months to get to BFS. As I see it from past history if we double that and then add another two years to finalise and build we are looking at another 4.5 years before this project gets of the ground. My history is based on Cobourn development!