I'm with OK4 Wire. It can't simply be written off as an "ETOPS planning exercise". You either have enough fuel or you don't.
In your example I would see it as a Diversion Decision Point plan and if insufficient fuel was found to be available at the critical point, divert for fuel.
Regards using the contingency fuel for the fuel available at the CP, I would think most companies would do it. In some cases it would be simply be due to a matter of fuel capacity, not commercial reasoning.
A different cost index can sometimes help.