Originally Posted by channa

This is NOT the same thing.

This is called end-on-end ticketing since you're going somewhere else on your nested ticket.

The OP's situation may be back-to-back ticketing since he's going back to his original point of departure.

The way to determine this is to see whether the new ticket assists him in violating the minimum stay requirements of the original ticket. If the original ticket had a 3-day min stay, and his new ticket helps him to break that, then he may be violating the rules. If, however, all his old ticket had was a Saturday night stay requirement, he's probably ok.