plans123
Are you suggesting by filing your flight plans as early as possible you get less of a delay? This is not the case if that is what you mean. If a regualtion is put in place it will affect all aircraft operating through regardless of the time it was filed at.
As G-MANN stated earlier you will find airlines operaing on longer routes as the countries they overfly have cheaper nav charges. A good example would be MAN-TFS to be filed via a Tango route.