Strange, I did not think about this, but all the long ICO that I saw gave worthy awards even for the value declared in advance, and not the one that is on the market.
Yes the earnings from bounty was not depend on how long it takes and even it takes too long that doesnt mean that you will get few earnings. It still depend on the campaign and on how long it is reach during the campaign. Never think that it was like that, just trust the manager and do your job as a participant of it.