The Never enough Budgets

The story is the same everywhere, Budgets planned in the beginning of the year are never adequate and consequently negative impact on the Packaging spends. Normally the Packaging Development Budget is somewhere a derivative of the Brand Plans and the spends are supposedly directional towards meeting those.
How often the Brand plans started off in the beginning of the year keep on changing and consequently the development work is either kept in abeyance or not used at all. In effect Packaging Budgets spent, output ready but as a consequence of the Brand plans changing the whole exercise becomes meaningless.
On the other hand the Brand plan stays but the Brief changes, consequently the Packaging budgets keep on depleting on the same project. Middle of the year when Packaging needs more budgets, the question that comes up , ' We did the same projects as per the Brand plan , so how come Packaging needs more Budgets'. Not understanding the fact that on the same project the brief kept changing or items kept getting added and the costs kept on building up.
The need for additional Budgets should be raised as soon as the brief changes on a project, thus the Packaging budgets should be a derivative of not only the Brand plans but also the brief and the scope of the work. Perhaps the Packaging budgets could be a Project wise allocation, subject to review of the deliverables and thus completely avoid the ' never enough ' syndrome.
Packaging which has the highest visibility often is the first to be on the chopping block and questioned for overdoing the brief. Offcourse all value additions are highly appreciated at the time of the launch, only to be later on dubbed as the costliest designer in the world.