All the above is true, but to add to that.... From what I understand, selecting Transition allows scheduling to adjust your end of month / beginning of next month sequences to meet legality needs, if you have conflicting sequences. You will get paid for days dropped, if any. By not choosing Transition, you will fly the whole last sequence of the remainder month, and any conflicting sequence on the following month will be dropped, if legality becomes an issue. You will not be paid for the dropped days in this case.