Yes but:
"If the rules include special winning conditions, Light and dark medals are awarded with respect to these new conditions; the best light solution will win the light medal, and the best dark solution will win a dark medal
if it is 'better' than the best light solution."
<quoted from c rules>
So, a 30 dark is not "better" than a 30 light, ("better" respect to the new conditions....)
In this case the condition is the score, not the money saved....
Therefore, a 30 light solution beats every dark one...
Or not?