ZIF-8 (body-centered, I-43m) obeys the selection rule "h+k+l=even survives" (from the preceding calculation); MOF-5 (face-centered, Fm-3m) obeys "h,k,l all even or all odd survives" (from the preceding calculation). Both are real nm-scale MOF frameworks with cubic cells an order of magnitude larger than simple inorganic salts. Does the fact that these two structures obey different systematic-absence rules mean that larger unit cells generally have different (or more restrictive) selection rules than small ones? Explain what actually determines each rule, using both structures' own computed results as evidence, and state what would and would not be established by comparing only these two examples.

This is a reasoning task over the already-computed MNI008 and MNI009 results; no new calculation or additional coordinate file is required. Do not recompute the structure factors; cite the two already-established patterns.