You miss the fact that their commission is paid one time for the period of 120 days, they lock your deposits for this period. So they pay 5% and use you money to trade 80 days (let us assume there are 80 working days in this 120 days period). Let us also assume they keep 0.2% in profits from the sum you invested, the rest of profits is being paid to other investors. Over these 80 days they make 16% and pay 5% in commission. Over larger amounts, this is a lot of money.
Also, do not consider arbitrage as only BTC-BTC trading process. There is BTC to fiat, alt coins to BTC, alt coins to alt coins. Lots of different exchanges and lots of opportunities. All I am saying that this is possible IMO.
Ok so let me try to follow you. I am referred by an affiliate and I decide to invest $100. The affiliate gets $5 upfront for the referral (5% x the value of each purchased Residual Income Share). Let us suppose the affiliate decides to withdraw that $5 commission. This would mean that Bitcoin trader now has $95 dollars with which to trade even though my account still shows a credit against it of $100. Over an 120 days period or 80 trading days they make a 16% return on $95, so $15.2 ($95 x 16%). So then out of this $15.2 trading profit they plug the hole $5 hole so to speak leaving $10.2 residual which is given back to you as profit on your initial investment of $100. Or am I still missing the point entirely??