Asians taking BC as seniors are rare-generally they will take Calc BC as juniors.
At least that’s the case in my son’s school and the Asian kid that takes BC as a senior or heaven forbid AB is an outlier. Although my son had 2 friends who are Chinese and ended up taking Calc AB. It didn’t hurt them much as one is going to NYU Stern and the other is at USC deciding between History and Marshall.