From sources inside the admin of Islamic banks, the money of the Islamic division and other divisions end up all to the same destination whether investment in projects or loans. It just have a different front end for marketing purpose and attracting more segments from the market to increase their market share and profitability.
And if it is really an Islamic division, why do we allow other non-Islamic transactions and legalize it!! My opinion....it is a big myth!
P.S. I am not against something being Islamic, but against fooling people.