If you'd like, I could ask the question to the very guy responsible for characteristic speed computation on Airbus SA.

A321 yesterday. There is definitely no VLS increase when Config 1 and Config 2 go out; it just drops away as you would expect.

On the youtube clip of the raw data approach you posted James, I think the speed brake is out - VLS is right up against the speed bug, so I think this brief few knots increase only occurs if the speed brake is deployed AND when only the slats are moving out.

There are a few threads that start on a wrong assumption and members enjoy giving free reign to their imagination. It never ends because nobody can produce an official answer nor anybody is ever sure that it really happens.

I hope that wasn't a dig at me vilas?

I have reported what I have seen in actual A320 and A321s when configuring for actual approaches.

I have watched the youtube clip James posted and have offered my observations about what I saw there and how I know the slats and flaps deploy on the A320 family.

KayPam has offered to find out the real reason, which seems reasonable.

Thank you for your observations Uplinker. Yes it's very obvious when the speedbrake is out!

It's actually pretty simple and should occur in all configurations (most easily seen when flaps are extending)
When flaps lever is in intermediate position, coefficients for the computation of VLS change (increase) due to A/C realizing it is not in a stable phase of flight

Thank you Kaypam

KayPam
Do you have a reference or you are just guessing? Because flap lever is not active in intermediate position?

My previous message on this topic was guestimating.

For the above, I do have a very precise reference but if I told you I would have to kill you thereafter :p
The reason I was given is because the design office considered the A/C to not be in a stable phase of flight when flap lever is moved.