Scaling Scatter Instances Keeping Positions Fixed

[Byteman3D]

As the title implies, I have a sphere with an animated noise, and a number of scattered objects depicting the spike proteins in a virus. (Title doesn't imply this, you're right. :D)
I need to make the scattered objects disappear as it enters the cell, and wish to scale them down to %0 as they cross the cell membrane.

Tried the Map mathod, with a max Gradient Map. My instances start to move as I move the UVW Map gizmo. Tried to achieve the effect with slice modifier, No go.

How can I resize th instances from one side to the opposite side to 0%, without changing the instances' placement?

[romullus]

Maybe try to achieve your goal without moving UVW map gizmo? You can animate gradient ramp map, or Scatter's scale spinners. Scatter relies on distribution object's UVs for scattered instances placement, so it's inevitable that instances will change their position if you will be altering UVs.

[Byteman3D]

Thank you. :) It works, yet I still have a problem.
The standard density I need is in the image. Switching to Map mode changes the distribution density and in order to gradually scale with a gradient, I can only think of creating a UVW more than double the size of the sphere make one half normal density and the other half scaled to zero  There will also be  a gradient area enough for the transition.Can't achieve the look I need.
How can I keep the density int the first place. Any tips?

[Aram Avetisyan]

Have you tried enabling temporal consistency?

[Byteman3D]

It is already enabled. The current problem is with planar mapping. I need it to scale down from one side but it creates a clustering effect 2 clusters in two opposite sides. Probably a very simple setting will scatter equally but couldn't find yet.

[Aram Avetisyan]

So distribution uses a UVW mapped texture, and so does the scale map?
Have you tried using different UV channels for those?