To get a uniform random (up to a maximum of 10% of the current value) change from current values in the VCS, you can hold down the Shift key while clicking the Dice button (or use Shift+R).
To generate the same result algorithmically within a Sound parameter field, you could use the randomWalk expression in Capytalk (use Ctrl+H to open the Capytalk reference and search for "randomWalk"). You could then use the Capytalk expression in the InterpolatePreset, for example, to randomly change the preset.
To generate the timing of the random gates, search in the Capytalk Reference for "brownian" to find the brownian noise trigger expressions.