RE Darby and the contract change:
I THINK that you will find that even with such a clause and placed in close enough proximity to what is being changed, they cannot change just anything. And even with such a clause, they might not be able to change anything at all anyway.
There are legal rules regarding what is acceptable in a contract, and I don't think that would pass legal muster -- a contract must be giving something specific for something specific. To be able to unilaterally change the terms any old way you want would not be giving anything -- for you could just change the terms to 0% interest and extend it to 15 years! They cannot just change any old part of the contract simply because they stick such a clause in it -- because that kind of use of such a clause isn't going to pass legal muster. But such a clause could make it legal to change the contract if BOTH PARTIES agree to it, with some outsider affected by that change -- say, a stockholder or other investor -- having no basis for challenging the change on the basis that the contract can't be changed.
As I said before, a lawyer will operate on the basis that its OK if you can get away with it.
I strongly urge any Darby customer, who wild have ground for complaint, to file a complaint with the FDIC so Darby will get in trouble -- and serve as a warning to other banks.