The visible mark does not show the depth
Liquid may have moved between the covering and filling. The visible patch therefore does not always show the full affected construction. Repeated incidents may involve parts of the base as well. A photo alone cannot support a reliable promise of complete odour removal.
Assess after drying
Agree at handover when and how to reassess the smell. Note whether it is constant or limited to certain areas. Added fragrances mask what you notice without locating the source. A persistent smell needs reassessment rather than an automatic repeat of the same method.
Treatment or replacement?
With deeply affected foam or inaccessible components, further cleaning may not be worthwhile. Ask about limitations and alternatives. Whether a cushion can be replaced needs checking with the furniture manufacturer or upholsterer; replacement is not automatically part of a cleaning service.