Anti-islanding certification is generally reported as pass or fail, although response times across the active- and reactive-power (P-Q) matrix contain additional information. We analyzed 925 Condition-A measurements from 37 grid-connected photovoltaic (PV) inverters tested under Korean Industrial Standard KS C 8565 at 60 Hz. A signed 5 × 5 map and within-product contrasts used each inverter as its own reference. Relatively long responses followed the ΔQ = 0 row rather than the balanced cell alone. Mean response was 0.221 s at balance, 0.140 s at signed |ΔQ| = 10% endpoints, and 0.208 s at signed |ΔP| = 10% endpoints. The direct P- versus Q-axis difference was 0.068 s (95% confidence interval (CI), 0.040–0.095 s; p < 0.001). Across the matrix, the ΔQ = 0 row exceeded the |ΔQ| = 10% rows by 0.061 s (95% CI, 0.036–0.085 s; p < 0.001). All values met the 0.5 s criterion. Reactive-power balance, rather than a single balanced cell, therefore marked a corridor of relatively long compliant response. This analysis converts certification records ordinarily summarized as pass/fail outcomes into a directional performance profile. The analysis procedure, but not the numerical PV response times, is proposed for future grid-connected power conversion system (PCS) testing, which requires separate charge- and discharge-mode validation.