FPSpreadsheet does not do anything with the FitToXXXX values - they are just passed on to Excel and appears in the "PageSetup" dialog, sheet "Paper format", box "Scaling", edit controls "Pages wide" and "Pages high" (these labels are translated from the German Excel version and may vary in the international version). I understand FitWidthToPages = 1 and FitHeightToPages = 1 such that the entire spreadsheet is scaled down to fit on 1 single printed page. FitWidthToPages = 2 and FitHeightToPages = 1 would scale the spreadsheet such that it fits on a virtual sheet which is 2 real pages wide and 1 page high.
I don't see Excel settings such as "fit on one page" or "fit all columns in one page". In my understanding, shouldn't they be the same?
If this does not answer your question please provide a sample data file, source code how you created the file and screenshots of what you want to achieve.