How big is your 4-page document source file?
I had an issue recently where one of my .process files grew to 34MB. There was a bug where it just kept inserting blank lines into one of the xml tags every time I saved it. But because it was constant, it compressed down in the archive quite well.
Rename the .LCA file to .ZIP, open it and see how big the files are in there. If there is one huge file, you might want to try copying the offending file to a new file in Workbench, delete the old one and see if that reduces the size.