Reading/writing to same spreadsheet

I'm uploading a spreadsheet, looping over the <cfspreadsheet> to create a query object of all the sheets. Then I'm using query of queries to get the columns I want, send those records to another query, which I want to loop over, do some calculations, then send those calcuations in a column on the very same spreadsheet (with each sheet having that column I need to fill in).

Does anybody know of any good spreadsheet tutorials that deal with dynamic data on multiple sheets? I can't find anything (official docs are no help).

I've never done it so this is just a guess, but you can try using SetActiveSheet/SetActiveSheetNumber to make a sheet active, and then use SetCellValue() to set the values. You'd obviously need to iterate over the sheets, activate each one, and update the values.