At first your line did not work here, but the errors were not reproduced and files opened in what might be .xml (I am ignorant on that.) I reset to starting state of vifmrc, commented out the references to LibreOffice.app and added the lines:
filetype {*.xls,*xlsx,*.ods,*.sc} sc-im %f
filextype {*.xls,*.xlsx,*.ods,*.sc} sc-im %f
and it works as expected. Your suggestion did work after all. Thank you!