Wow, that is my phone’s best auto correct! Sorry about the sloppiness of that post. Very much my bad.
I believe I meant to say that there is an additional amount of $4k in Student Direct Loans permitted for dependent students taking an additional semester or year beyond the 4 years. I mistakenly quoted the $31K over 4 years in an earlier post. The amounts a student can borrow are $5500 as a freshman, $6500 as a sophomore, $7500 a year thereafter with $4k left once $27k total has been borrowed with no principle paid back.
But OP seems to have that part down pat. The aid package apparently includes loans; the DD will be taking loans, but there is a shortfall of $15k. How much of that OP is willing and able to pay out of pocket, we do not know. But some amount he wants to borrow so he does not break into the 529 as a noncustodial parent because that could affect aid two years later.