Finite-Barrier Double-Slit Scattering in Standard Quantum Mechanics: Numerical Separation of Through-Thickness and Finite-Wall Responses

We investigate finite-potential, finite-thickness electron double-slit scattering entirely within the time-dependent Schrödinger equation, using controlled numerical simulations and independently documented computational records. Three principal findings are retained after numerical and adversarial checks. First, a sharp spatial partition between material and aperture contributions is not unique: small shifts in the partition can change the assigned bulk contribution and reverse its sign. Second, barrier-thickness scans distinguish a through-thickness transmission contribution, independently calibrated using a no-slit geometry, from a finite-wall scattering residual that persists when direct barrier transmission becomes very small. Third, wall-height scans relative to a finite 8 eV control demonstrate a sign reversal of the detector-flux difference, with height and thickness dependences transported using one fitted geometry constant. The physical carrier responsible for the wall-height dependence remains unidentified, as a null carrier performs comparably within current numerical systematics. Simulation A is supported by a regenerable numerical package and verification infrastructure; Simulation B provides a frozen, independently developed outcome record, but its historical raw solver archive was not preserved. The two records are not represented as point-by-point numerical replications. The study presents a constrained numerical characterization of finite-wall scattering and boundary-condition sensitivity. It introduces no additional quantum propagation path, Born-rule violation, or physical dynamics beyond standard nonrelativistic quantum mechanics.