Which is more accurate?

Hello,

I'm keen to pick the V-Flyer brains, as I'm sure somebody on here will be able to explain this to me....

I'm travelling back from SFO in June on the VS42 and I'm really keen to see if it will be an A340-300 or a 600. I know the 300 is scheduled on this route however when I log into manage my booking it shows the seat map for the A340-600.

I did a dummy booking on the same date to check if the aircraft had indeed changed and Virgin's booking engine still shows the 300. So my questions is, which is more accurate? Manage my booking or Virgin's actual booking tool?

If Virgin has put the 600 onto this route, would they know that this far in advance (due to a heavy load perhaps) or are such changes only operational and therefore done at the last minute?

I'm getting sleepless night wondering if I will have vport or not (yes I did just admit that!!). So I'm really hoping the Manage My Booking section is accurate

On the few flights so far VS has mixed the A343 and A346 - the schedule calendar shows 2 out of 7 in May have been an A346. I'm on the VS42 on 8 June and its scheduled to be an A346. If the seatmap shows the bigger bird, then I'd suggest it is correct. Of course, it can change though.

Looking at EF for my flight dates it looks like the second SFO flight is a success, at least on some days, so justifying the larger aircraft:

VS20 J1 C1 D1 I0 Z0 W3 S2 K1 Y0 B0 R0 L0 U0 M0 E0 Q0 X0 N0 O0

VS42 J2 C2 D2 I1 Z1 W0 S0 K0 Y9 B9 R9 L9 U9 M9 E9 Q9 X8 N3 O0