I am posting this as information ; I don't expect there to be a solution.
I noticed that file sizes were increased dramatically when updated by LO so I conducted a test by creating duplicates of two files which are updated using a series of macros and data from a .csv file. The results are as follows :
File 1 ( a spreadsheet ) and a copy were each 97.7KiB prior to update. When the original file was updated by OpenOffice, it grew in size to 98.0KiB. When the copy was updated by LO, it grew to 146.3KiB.
File 2 ( a spreadsheet ) and a copy were each 169.4KiB prior to update. When the original was updated by OpenOffice, it grew to 169.9KiB. When the copy was updated by LO, it grew to 206.9KiB.