I'd go to BU if I were you. It would be different if you are talking about a respectable school such as Cordozo, Pepperdine, Loyola, American, whatever (low T1-T2 type school), but I'm guessing the OCI at your T4 is basically non-existent so the fact that BU's OCI date has already passed is a wash. At least you can still conduct the exact same mailing campaign but you can do it with BU's name on your resume so that you can get some added attention. T4 is just too low and will make it a lot harder on your job prospects for the rest of your life. This is all assuming, of course, that you actually care about making money and advancing your career.