The CopySheet method is intended to allow for copying of sheets from one position to another within a single workbook. To copy content from a worksheet in one workbook to worksheet in another workbook, use the Worksheet.CopyPaste
All of the settings, configuration, and values on the original worksheet will be both preserved on the original worksheet and copied to the new worksheet. If there are any formulas in the worksheet that is copied that reference that worksheet, they will be updated to reference the new worksheet instead. Formulas on the original worksheet and on other worksheets will not be affected.
Copysheet was extended to support copying worksheets between workbooks for XLSX and XLSM files.