LOL... I believe he knows that! :D (from a different forum)...
Thing is that composing for orchestra is SO MUCH more than just doubling and 'just' thinking in colors. It's all the range, the dynamics, the colors (yes, ok), the phrasings, the everything. It's not an easy going path by all means.
Of course I have composed 'tons' of orchestral music, either for my PhD (which never got performed to be honest, so I'm not 'counting them'), either for computer games and virtual instruments. I know my way around an orchestra, but it's only very recently that I started feeling more secure, or confident enough to start knocking on doors and grabing commissions and arrange for performances...
Anyhow froggy: Best of luck in the competition! ;)