Hi, the cut offs for DU colleges in arts stream is always quite high, especially for 1st tier colleges because of the courses being in high demand i.e huge numbers of aspirants applying for the course from all over India. With 80.6% your chances are quite less and after applying for a stream change(commerce to arts) further 2.5% will be deducted from your best of four percentage. So, unfortunately it will be every difficult for you get admission.

Good Luck