1) Film speed and development are independent
2) ISO exposure is the minimum exposure needed for a quality print under controlled conditions.
3) There is no ISO standard for the maximum exposure tolerable to make a quality print...therefore
4) There is no ISO standard measure of film latitude
5) Most all contemporary B&W films will exceed the range of the common 21 step wedge...therefore
6) It is somewhat difficult to have a meaningful discussion of B&W film latitude