If a transaction description on your Mediobanca statement is long enough to wrap across two or three lines, it still needs to land in a single row once converted. Transaction descriptions that wrap across several lines are treated as a single entry. The engine recognises when text belongs to the row above rather than starting a new record, so multi-line narratives stay intact and out of adjacent columns.
If the running balance on your Mediobanca statement does not add up row by row, that is exactly the kind of mismatch Convert·Into is built to catch rather than pass through silently. The running balance is checked against the closing figure printed on the statement itself. If a row does not add up, it is flagged for review; a single mismatch never blocks the rest of the file from being processed and exported.