The ‘Read and Write Excel’ Plugin can do exactly what you want. You can install it via the Fiji updater (look for ‘ResultsToExcel’). Then in a macro, your call will look something like this:
run("Read and Write Excel", "file=[C:/Users/kisha/Documents/My_cool_file.xlsx] sheet=[Custom name here] dataset_label=[name of processed image etc]");
In which ‘file’ denotes the save and re-write location and file-name (if not provided, the users desktop and a deafult title is used); ‘sheet’ denotes the workbook tab (if the same tab-name is given then that tab will be updated. If a new tab name is given, a new tab will be created); and ‘dataset_label’ denotes the data import label (by default the last open image title will be used).
Other instructions can be found here:
Only bringing this to your attention in case it can help. ImageJ of course has plenty of native functionality for .csv and .txt saving. With clever macro file opening and data parsing the same file/data can be amended but this plugin does make it easier.