Kernrechtsfrage
Whether the cantonal court arbitrarily assessed the evidence and found an agreed open account rather than a fixed lump-sum price.
Extrahierter Entscheid
No arbitrariness was shown; the cantonal court could infer from the contract, cost estimates, and the parties' subsequent conduct that the remuneration was to be settled according to work value and expenses.
Extrahierte Begründung
The challenge did not demonstrate that decisive evidence had been ignored or assessed in an obviously untenable way. The court could rely on the absence of a detailed work specification, the higher cost estimates, and the parties' conduct during construction.