You do have a point and one we had to consider. As per the OP I think the DGEX commission they have set is 3% of funds managed. So there most certainly is a self interest in raising a large amount of funds. That being said, as I just mentioned in another comment, I don't think anyone will hit the 10% mark and the previous high they saw was 6% from one investor.
Of course it is unlikely that the 10% mark will be hit, as it is obvious DGEX wants as much BTC invested as possible.
They will suggest a mark that is so high it is very unlikely it will be hit. That way, the maximum amount of invested BTC from every single person can be guaranteed.
And 6% of all coins in the hands of a single investor is a ticking time bomb already.
NXT had and has to face accusations of bad distribution and their top account only held 5% of everyting.
As was later shown, I was wrong in this post considering Dgex motives. The information I commented upon was false.