I tried to say something BUT its Gone into space... So will try again.
Those numbers seem a bit fishy to me... 180 mins 65 buckets.
Thats 2.8 mins round trip ( to and from the fire) ! thats 1.4 mins each way WITHOUT taking into account slowing down and transition to pick up water and back to flight then dump the water and go again! If that was the case on that fire the water must of been beside the fire! NOT too many fires with the luxury of water right beside the fire that I have been on!
Butni might do the numbers next time i ever get water that close to the fire, and work out the cost per litre involved.
Accountants can make numbers talk BUT each job has its own problems, Trees around the wat point, windy escarpments, wires etc!