Wow. Learn something new every day.
Is this a new feature? If yes, do I need to re-import old txt files?
I ask because I have 1600 txt files in my library totally 176 MB and the size of "field (text).jmd" is only 10 MB so something does not add up.
it has been there for quite a while, so i dont think you need to reimport (you could update library from tags), maybe you have some textfiles with "wrong" encoding..but that is just a guess..also MC compress quite hard so the figures may look wrong, when they are actually not.
but to check, add expression length([text]) and sort..(and maybe combine that with math() and file size, ) you will then see if there are something wrong..