Your maths is just stupid. Sorry I'm a housing bear but your logic and maths is way off. If you borrow all the money then you don't have money to stick on the bank and earn 6%. In this case you would be 5.5% better off. If you have the money in the bank you don't have to borrow it at 7.5%. Hence you will be 4% better off. (6% return rather than 2%). If you think you can add .5 and 6% together to say you are 11.5% better off I think you had better do some more thinking about your maths and logic.