Are GC'd documents larger than Non-GC docs?

Is the average size of a garbage-collected document expected to be larger than a not GC’d document?

I’m converting a large number of non-GC’d documents to their equivalent GC’d version, and I’m finding the average size of documents is actually increasing significantly. Am I doing something wrong, or is this expected?

Documents with very large runs of data and deletes have a much smaller post-GC size, as expected, but the vast majority of GC’d docs are 10-30% larger.

EDIT: Nevermind, there was an encoding mistake in my logging code.