Parts fill rates and the lost sales that never reach the counter

Parts fill rate looks healthy until you notice how few lost-sale tickets the counter files. In many Bangkok workshops, advisors learn which SKUs routinely sit on back order and simply stop offering them. The fill rate rises; the customer leaves with an incomplete job or a deferred visit.

Pair the official lost-sale log with a sample of ROs where labour was billed but key wear items were absent. Look for brake pads without fluid flush, cabin filters skipped on 20,000 km services, and battery tests that never become battery sales. Those gaps rarely appear in the lost-sale file.

Talk to the counter about substitution habits. A high fill rate built on aggressive substitutes can still damage CSI when the customer expected the franchise-branded part. Note which substitutes the OEM allows and which ones the advisor has to explain awkwardly at handover.

When we run a Parts & Labour Margin Brief, we ask for both the lost-sale export and a week of reception recordings or notes if the site keeps them. The combination usually reveals a quieter leakage pattern than the fill-rate percentage alone.