Trade Offs Between Metrics and Guardrails Questions

WITH metrics AS (
  SELECT
    date,
    variant,
    metric_value AS primary_val,
    guardrail_value AS guardrail_val
  FROM daily_metrics
),
rolling AS (
  SELECT
    date,
    variant,
    -- current 7-day avg ending on this date
    AVG(primary_val) OVER (PARTITION BY variant ORDER BY date ROWS BETWEEN 6 PRECEDING AND CURRENT ROW) AS primary_7d,
    AVG(primary_val) OVER (PARTITION BY variant ORDER BY date ROWS BETWEEN 13 PRECEDING AND 7 PRECEDING) AS primary_baseline_7d,
    AVG(guardrail_val) OVER (PARTITION BY variant ORDER BY date ROWS BETWEEN 6 PRECEDING AND CURRENT ROW) AS guardrail_7d,
    AVG(guardrail_val) OVER (PARTITION BY variant ORDER BY date ROWS BETWEEN 13 PRECEDING AND 7 PRECEDING) AS guardrail_baseline_7d
  FROM metrics
)
SELECT
  date,
  variant,
  primary_7d,
  primary_baseline_7d,
  CASE WHEN primary_baseline_7d IS NULL OR primary_baseline_7d = 0 THEN NULL
       ELSE (primary_7d - primary_baseline_7d) / primary_baseline_7d END AS primary_pct_change,
  guardrail_7d,
  guardrail_baseline_7d,
  CASE WHEN guardrail_baseline_7d IS NULL OR guardrail_baseline_7d = 0 THEN NULL
       ELSE (guardrail_7d - guardrail_baseline_7d) / guardrail_baseline_7d END AS guardrail_pct_change,
  -- threshold e.g., 0.10 for 10%
  CASE WHEN ABS((primary_7d - primary_baseline_7d) / NULLIF(primary_baseline_7d,0)) > 0.10
            OR ABS((guardrail_7d - guardrail_baseline_7d) / NULLIF(guardrail_baseline_7d,0)) > 0.10
       THEN TRUE ELSE FALSE END AS alert
FROM rolling
ORDER BY variant, date;