VS45 tomorrow (Friday)

Question 2 -- feeling inquisitive today!
The VS45 tomorrow has had a plane change from 747 to A346. Does anyone know why this may be out of curiosity? When I last checked on flightstat before change of aircraft there were loads of seats (9+ for all classes) available, but after the change now the only class with availability is J. Running a dummy booking on VS website indicates the same. Is it as overbooked as I think it might be? (I have had the privilege of a red voucher before... and it was brill).
Not just being nosy - I'm booked to be on that flight (in Y) tomorrow.
The VS45 tomorrow has had a plane change from 747 to A346. Does anyone know why this may be out of curiosity? When I last checked on flightstat before change of aircraft there were loads of seats (9+ for all classes) available, but after the change now the only class with availability is J. Running a dummy booking on VS website indicates the same. Is it as overbooked as I think it might be? (I have had the privilege of a red voucher before... and it was brill).
Not just being nosy - I'm booked to be on that flight (in Y) tomorrow.
