The Cross-Border Compliance Stack: Why EU CPO Expansion Slows After the First Market and What the AFIR Review Can Fix

AFIR sets a single regulatory floor across all 27 EU member states, but a CPO that achieves full compliance in its home market is not compliant in the next one. This paper maps a four-layer compliance stack, EU baseline obligations, national transposition instruments, hardware protocol variance, and DSO connection queues, that compounds non-linearly as growth-phase charge point operators expand cross-border. Drawing on a composite 200 to 500 charger operator profile and concrete country-pair analysis across the Netherlands, Germany, Spain, and Portugal, the paper introduces a Regulatory Maturity Classification that sorts national instruments by whether they solve a current EU-wide problem, a future one, or one already superseded by EU standards. It quantifies the financial consequence: carry costs, hardware recertification delays, and a utilisation timing mismatch that compress investor returns below standard acquisition assumptions, and shows how this drives market consolidation toward large operators able to absorb compliance cost as overhead while growth-phase entrants retreat to markets they already understand, a pattern that runs directly counter to AFIR's deployment objectives. The paper closes with three recommendations for the AFIR mandatory review, open for public consultation through 3 August 2026: consolidating non-binding Article 5 guidance into binding technical standards, establishing a single EU-level EVSE hardware type approval registry, and mandating a minimum OCPP version with built-in forward compatibility, the last independently corroborated by CharIN's own submission to the same review.