Hi,
Thanks for using Aspose.Cells.
We are afraid, Aspose.Cells cannot save the automatic value of XLS file (i.e. Saved by MS-Excel 2007 or later version) to XLSX.
In XLS (Saved by MS-Excel 2007), the automatic value is false. We can find some other unknown information of chart. But we cannot make sure it is the setting of automatic value. Now we don't support reading the unknown information.
Please check the attachment (i.e. 1496.zip).
CreateByExcel2003.xls is saved by MS-Excel 2007, CreateByExcel2007.xls is saved by MS-Excel 2016. The two other files are saved by Aspose.Cells. We can find CreateByExcel2003.xls.Save.xlsx is right.