A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Just to update in regards to the other person who had the same issue.
He did a clean uninstall of his PC and Office. Reinstalled the English version instead of using his original Japanese version. The missing options (Txt Mac and MS-DOS and CSV Mac and MS-DOS) were now available for him to save as.
After that, he installed the Japanese language pack for his excel and those options disappeared again.
It seems to be that you can only have these options in the English version. Any other language (Not sure if all but at this current point in time, Japanese and Chinese are confirmed not adaptable) will remove them from the Save as type list.