VS17/18 Aircraft Data

Hi All,
I have just put some flights on hold in November 2005
VS17 out and VS18 back.
Now the VFlyer Db tells me that 100% of the time both of these flights are flown by an airbus of some kind (Mainly A340-600).
The premier team have just informed me that this will be a j2000 equiped airbus (so I assume it is a A340-300) on VS17 and a 747-400 on the return leg.
So I have 4 questions.
1) Does the VFlyer db work out its percentages from the last 3 months travel only
2) Do Virgin fly different aircraft in the winter months due to demand?
3) What are the chances of these aircraft being changed or being updgraded from j2000 to UCS before I fly.
4) Are all 346's now UCS?
Any other info on this route appreciated. I have flown this route many times but can't remember the last time I flew so late in the year.
Paul
I have just put some flights on hold in November 2005
VS17 out and VS18 back.
Now the VFlyer Db tells me that 100% of the time both of these flights are flown by an airbus of some kind (Mainly A340-600).
The premier team have just informed me that this will be a j2000 equiped airbus (so I assume it is a A340-300) on VS17 and a 747-400 on the return leg.
So I have 4 questions.
1) Does the VFlyer db work out its percentages from the last 3 months travel only
2) Do Virgin fly different aircraft in the winter months due to demand?
3) What are the chances of these aircraft being changed or being updgraded from j2000 to UCS before I fly.
4) Are all 346's now UCS?
Any other info on this route appreciated. I have flown this route many times but can't remember the last time I flew so late in the year.
Paul