Hierarchical Filtering of Coherence Leakage and Justification of the Exponent 18 in PDL

This note presents a minimal justification of the integer exponent 18 that appears in the hierarchical amplification of the coherence – leakage parameter in the Projective Dynamic Logo (PDL). We interpret εε as a local combinatorial defect of closure at the proton level and organise the propagation of this leakage through three successive organisational scales: proton architecture, nuclear structure, and ordinary matter with an emergent metric regime. Each scale contributes a finite set of independent coherence filters, yielding a total of 18 logically distinct constraints that any leakage must satisfy before it can manifest as a universal effective gravitational coupling. The goal is not to provide a full combinatorial proof, but to make explicit the structural counting scheme that underlies the choice of the exponent 18.