I think I have penetrated the linguistic subtleties of all this.
Reformulation means changing the formula. The recipe. This might be changing rose for lavender, or apples for oranges.
However, getting rid of the Taif Rose essence and replacing it with a nice new synthetic rose, or . . . when it comes to making a good Screwdriver, switching the pure juice squeezed from fresh oranges just off the plane from Italy for O.J from the supermarket fridge at the mall is not reformulation . . . the recipe has not changed, just the quality of the ingredients. And we decided to 'hold the vodka' a bit, so the quantity has changed a bit, too.
Same formula, though