Farid

One practical observation from having watched this go wrong: a top tier that is wildly out of proportion can damage trust rather than anchor.

If the plans run 10, 30, 90 and then 2000, the last number does not make 90 look reasonable — it makes people wonder what the real price is and whether they are being played. The anchoring effect has a range beyond which it turns into suspicion.

In the cases I have seen, the useful top tier is somewhere around two to four times the target plan and is clearly aimed at an identifiable kind of customer. Beyond that you are not anchoring, you are performing.

Consider whether you need the dialog at all, because the best version of this problem is the one you deleted.

Two alternatives that remove it:

• Autosave the draft. Closing then loses nothing; reopening restores what they typed. This is strictly better whenever it is feasible, and it turns an interruption into a non-event.
• Make closing undoable. Close immediately, show a brief "Draft discarded — Undo" notice. The user is not blocked, the mistake is recoverable, and the common case, where they genuinely meant to close, costs them nothing.

Confirmation dialogs are a tax on every correct action to protect against an occasional incorrect one. When the incorrect one can be made recoverable instead, that is nearly always the better trade.

There is a cheaper intervention worth knowing about, which is to stop all four cars serving all floors identically.

Splitting the bank — two cars serving lower floors, two serving upper, or one car reserved for the top floors and roof — reduces the average number of stops per trip without any new hardware or any new interface. It is why tall buildings have sky lobbies and express cars.

The trade is fairness: somebody's floor is now served by two lifts instead of four, and they will notice. In a residential building that is a political problem rather than an engineering one, which is often why it does not happen.