I am seeing some very strange behavior. In the attached workbook, cell B1726 on the Input sheet has formula =B1725. In memory in my C# program, after CalculateFormula is called for the workbook, I can see the DoubleVal…...that differ from the original data after calling Cell.PutValue...a1Style = a1.GetStyle(); a1Style.Custom = "0.00%"; a1.SetStyle(a1Style);...