Shatter AND Shove

[Ambiorix]

When you roll an S or Skull during a charge combat with a troop type that has both characteristics, is the effect
on neighboring files cumulative, i.e. causing an extra +3

[Francis Small]

You only get the best one - shatter - for a +2. On the QRS where it describes an S result it says "Shatter or shove...", and this is interpreted to mean you only get one or the other. Think of shatter as super form of shove, not something separate from shove.