As you pay back the loan, your payments may change if your credit line has a variable interest rate, even if you do not borrow more money from your account. (mortgage-x.com)
A debt ceiling means the treasury can't borrow more money by way of issuing new bonds (see below for some history). (politics.stackexchange.com)
But you paid them by borrowing more money for the larger cost of the home. (creditdonkey.com)