chore: remove boarding point price levelling

docs/buspro-database-reference.md

@@ -225,16 +225,12 @@ JOIN dbo.ZustiegPreis zp ON zp.IDArtZustiegPreis_FS=lb.IDArtZustiegPreis_FS
 WHERE l.IDLeistung IN (@OutboundServiceId,@ReturnServiceId);
 ```
 
-**V 2026-09-28 — the XML export can omit the return-leg price.** Since one price row is
-surfaced twice, an asymmetric pair is an export defect: on products 701 and 2435 a
-`<zustieg_rueck>` carries no `preis` although the engine still bills the return
-`Abfahrtsortzuschlag`, so reading the export verbatim undercharges by one leg. Measured over
-all exports, a stated return price never differs from its outbound counterpart (510 pairs,
-zero counter-examples). `TravelParser` therefore levels a boarding point's price across both
-directions, switchable through `APP_BPN_LEVEL_BOARDING_POINT_PRICES` while the defect is open
-with the vendor. Flipping the flag needs `app:bpn:xml-cache-invalidate` and
-`app:bpn:refresh-travel-snapshot`. A point appearing **only** in `zustiege_rueck` without a
-price cannot be priced from our side — that is a catalog job.
+**V 2026-10-02 — an unpriced return leg is free.** The export can state a `preis` on the
+outbound `<zustieg>` but none on the matching `<zustieg_rueck>` (seen on products 701 and
+2435). The booking engine bills a return `Abfahrtsortzuschlag` only where the return entry
+states a price, so the export is read verbatim, per leg. A missing return price is a catalog
+omission for the office to fix, not something to compensate locally: pricing the return leg
+from the outbound one makes the booking inquiry fail with a price mismatch.
 
 **N — the departure surcharge is computed.** Booking responses carry a position
 `art="SON" unterart="TRA"` (*Abfahrtsortzuschlag*) with no matching row type: `ArtZuschlag`