When is a one-click upsell unauthorised, not convenient

What this step is

Step 39 (Part VI) is marked hard difficulty, often skipped, which is unusual for a step this close to step 37 and 38 (saving the card, pricing the bump), both marked easy. The difficulty sits in the fallback path, not the happy path.

Matching consent to price

A one-click charge is fine at a small amount. At several hundred dollars it reads as unauthorised. Send the buyer through a real checkout with a visible total above a threshold you set and write down, as a judgement call, not a formula.

The off-session fallback

An off-session charge, made with nobody present to approve it, reuses a saved payment method and mostly succeeds silently. A minority need the card's issuing bank to confirm first, which arrives as a routing status, not an error. Treat it as a routing instruction: send the buyer to a hosted payment page for the same amount, so the sale still lands with one-click-level tracking intact rather than falling back to a generic checkout that loses the attribution.

What done looks like

A written threshold, a one-click path below it, a full checkout with a visible total above it, and a routing-status fallback that catches the minority of banks that need to confirm first without losing the sale or the tracking.

The threshold itself is a judgement call, not a formula the matrix or the Field Manual hands over as a fixed number; what's fixed is the rule that the threshold has to be written down and applied consistently, rather than decided ad hoc per offer.

Where it breaks

Treating the bank's confirmation requirement as a failed charge instead of a routing instruction, which loses sales that would have completed on the fallback page. Setting no written threshold at all, so every upsell runs one-click regardless of price, which is the exact failure the rule exists to prevent.