[autoprecise1]

Assuming from the information you gave. Your hood has single stage paint on it. Before you buffed it/polished it was the hood more dull then the other panels? More than likely it was. A vehicle does not necessarily have to be in an accident to have one panel repainted, and it is highly unusal to have just the hood fade and the others not (from a factory coat of paint). Normally fading from factory paint occurs on the bumper areas and not the hood. If it does occur on the hood then the other top panels will begin to do the same thing (roof and trunk). So, I believe your hood has been repainted in a Single Stage coat of paint. Something you are stuck with, unless you have the hood repainted with a base coat/clear coat.
So solution:
buff/polish to your likeing
keep a good coat of wax/protectant on it to keep up the shine, eventually you more than likely have to buff it all over again, but up keep will help the shine last longer.