“ Maximum sales prices for the two houses had been stipulated by respondents in securing the permission to build required under Priorities Regulation 33. [2] Statutory authority for that regulation had been repealed before the sale of respondents' houses, except for a proviso continuing in full force and effect priorities for building materials issued under the Veterans' Emergency Housing Act of 1946. [3] The Government views the maximum prices stipulated by respondents as a condition of construction authorization and priorities assistance that survived repeal under the proviso. ”