Mike,
the .mcx files are the compiled versions of the .mac files, which are opened and saved in cognos scripteditor. No need to muck around with .mcx files as if you run the .mac file, the .mcx version is generated.
Best to do all within the .mac file - set the variables and objects, open impromptu, run the reports and save as required, close impromptu and do further bits and bobs (eg emailing, excel formatting on the xls versions) prior to ending the macro.
lex
soi la, soi carre