You should get the APA Product Data & Application Binder. This has all their publications for cheap and covers these issues as well as design tables.
In "Introduction to Lateral Design" Table 1 the footnote says this:
Design for diaphrahm stresses depends on direction of continuous panel joints with reference to load, not on direction of long dimension of sheet. Continuous framing may be in either direction for blocked diaphragms. It then goes on to describe 6 cases.
For a random example from the table, Case I (No unblocked edges or continuous joints parallel to load) has a shear of 165 plf. All the other cases are the same at 125plf.