IOWA CITY — Just four years after University of Iowa Health Care opened its 14-story, $392.7 million Stead Family Children’s Hospital — and after design changes and cost overruns pushed the project $122 million over budget — the hospital is asking to spend another $10 to $15 million to replace two floors of windows.If the Board of Regents next week approves replacing windows on Floors 4 and 5 of the Children’s Hospital — and on a connector bridge leading to the main UIHC campus — it will swell the project’s total cost to over $407 million.That price still does not include costs for consulting and assessments to determine which windows pose a risk and the cause of the deficiencies.