Report P10, P50 and P90 demand for every A-class SKU. Buy to P50 and hold safety stock to cover the gap to P80 on your highest-margin items only.
Model lead-time variability separately from demand variability. Combining them into one buffer is why brands both stock out and overstock in the same quarter.
Re-forecast weekly for the top 20 SKUs, monthly for everything else. Daily re-forecasting adds noise, not accuracy.
