It's about Volkhov/Dvina family. We all know, that if we can launch a missile without tracking the target. When the missile drop the first stage and start receiving commands from SNR, it must follow the boresights position at the moment (after some oscilations). I think it is like RS should be.

Correct.

As I see missile reacts just like that on epsilon and beta, ut still can't figure it out is moving the range boresight reflecting on missile, or not.

Basically you should see no effect, except for K method, where the added elevation is depending on target range.

Also, when practicing on Ashuluk in UPR/K:
- against supersonic target the lead hits 4 degrees mark
- against subsonic target - lead is not more than 3 degrees

Correct.
Subsonic target UPR point is closer to the target. It can be less than 4 degree, depending on the P.
Supersonic target UPR point is further to the target. It can be more than 4 degree, but the system allows the missile max 4 degree.

When the missile is flying at less than 4 degree, than it is directly goes towards the UPR point.
When the missile is flying at 4 degree, than the UPR point is at probably more than 4 degree, just the system limits its lead angle.