Well, Aspose.Cells follows MS Excel standards and specifications when merging cells into a single cell. Could you please provide us sample code (runnable) with input Excel file (if you have any). Also provide your output file by Aspose.Cells. Moreover, please provide your expected file which you may create it (after merging operation in MS Excel) manually in MS Excel, we will check it soon.
Good to know that you have sorted your issue out. Feel free to contact us any time if you need further help or have some other issue or queries, we will be happy to assist you soon.