Notwithstanding any annual budget or statute relating thereto, any city of the first class owning and operating a public utility, or the city's public utility department, may make an adjustment or change of the rate of daily wages of employees of any such public utility if such adjustment or change is accompanied by or is approximately coincidental with a shortening of the workweek of the employees and if the adjustment or change will not result in any increase in pay per week, or excess of expenditures of the public utility over its revenues.