I expect that to be simply because the maps have grown, not because of the fragmenting. I just updated all my maps (15 areas, including Germany already fragmented before the update) and the total space taken has increased by about 1 GB. I now have only 1 GB left free on a 16 GB SD card

Whilst on the topic, rinigus, would it be possible to update one map at a time? I did not see such an option, I had to update them all in one large go taking a few hours.