This study highlights significant variability in combustibility classification results for flame-retardant plywood across different laboratories, despite adherence to the Russian State Standard GOST 30244–94 “Building materials. Methods for testing combustibility”. Proposed improvements—such as standardizing gas type, optimizing sample clamps and air supply to reduce multidirectional airflow, and implementing stringent calibration protocols—may enhance measurement reliability. However, these measures do not address the core issue: the lack of a clear linkage between physicochemical combustion processes, test parameters, and predictive indicators of material behavior in fire. A holistic approach assessing heat release, flame spread, smoke density, and other objective metrics is essential for accurate characterization of material fire performance. Current regulatory combustibility metrics insufficiently represent actual fire hazards, limiting their use in fire safety regulation and prediction. Development of a unified classification system integrating advanced analytical methods is critical for improving the accuracy of fire prediction models and develop more effective fire protection strategies.