Jetblue airfare- much less for booking RT?

[frannn]

Priced out airfare for our mid May trip. Usually there's like a $10-20 difference for booking each leg of the trip separate instead of booking RT all at once. Booking each leg separate is preferred because its easier to change/cancel if necessary but for this May it was $177 RT each compared to $258 RT if we booked each way separately. Is this something new or have I just gotten lucky in the past? Any other benefits/issues with booking the RT all at once?