Seems Delta/virgin are still playing about with their April flights.
Seems a few anomalies in the system such as no DL ATL-MAN bookable on Thursdays but then the MAN-ATL is bookable for the return. Sunday's that the DL B777 operates also sees the departure moved from 1015 to 1325 for what seems no real reason as the aircraft arrives at 0820 just like the other 2 days for the 1015 departure.
Also seems a lot of dates in April that VS doesn't operate any MCO at all, which considering its around the time of half terms, is slightly odd?