
How I compute the real, point-inclusive price — design notes from a 3-layer model
Building a price watcher on my own, the calculation I underestimated most was 'display price minus the points you earn'. Splitting reward points into three certainty layers (confirmed, conditional, assumed), flooring each layer before summing, ranking on the confirmed layer only, and why shipping stays out — the design decisions I landed on, with code.

























































