Strikes me that the industry has sadly moved nearer the "jobsworth" it seems.
When I started out load planning/dispatching we didn't have them new fangled computer thingys yet and used a combination of checking the weather, tables and manual calcs to arrive at a fuel figure (and don't get me started on some of the new breed who can only punch in numbers with no actual understanding!!)
But .... we were very clear that the person who had the final say was the one that had to leave the ground.
It was also a matter of professional pride that we felt the job was done well when the Capt. agreed our fuel figure unchanged.
It was re-assuring that if we'd proposed max fuel or min fuel or whatever in between when that was agreed as suitable. Of course we knew we were right
... but corrobaration that we were both right (or wrong!) was always welcome.
But ..... the place for "challenging" the Capt's decision on fuel is not on the day, pre-flight etc.
I find that tone a tad disturbing really .... we worked as a team and decisions such as this were made in that spirit ... it's a sad day if the beancounters have created a possible tension were one did not exist...