I frequently have to do this because "pending" tranactions are not downloaded but ARE included in the online balance. Since there are generally at most one or two of these, I just enter them by hand if they are not already there, and then tick them off in the reconcile window to get it balanced.
Or it could have been, if you re-download a date range in order to catch a missing or mis-matched transaction.
Correct. Suppose you don't electronically retrieve you transactions at all.