Correct, I think. If I was unclear on the tradeoffs I did intend to imply that splitting on a delimiter, even if it's a delimiter near the middle of the file, will almost never result in both sides of the split being of identical size. If you're forced to split into identical sizes on a file where the physical middle is not guaranteed to fall on a record boundary, then you must necessarily lose record-oriented semantics, or deal with the record that spans the physical middle of the file being broken.

I suspect that in this individual's case, it's a reasonable tradeoff for each file to be approximately equal in size to the extent that retaining logical record integrity permits. That is, records are more important than exact size.