>>4570976975. Psyshock and Secret sword set the benchmark of 80-85 BP for moves that you consciously choose to switch to the other type of defense ahead of time and can't adjust on the fly. For one that change on the fly to whatever option is best, then the BP should probably be a tad lower than those, so 75 seems reasonable.
You could justify 70 if on an offensively powerful type or 80 if it was on an offensively unimpressive type.
