If you check the "B version active" checkbox on the moment properties tab you can create an alternate version of the state updates for the selected moment.

You can use this any way you want but some things it can be useful for include:

• Roughly modeling and comparing different player strategies or difficulty levels. e.g. a player who uses a normal combat strategy is represented in the A version of the updates; a player who plays using a no-kills/expert strategy is modelled using the B updates.
• Modelling mission success vs mission fail states
• Modelling upper and lower limits. For example, say you estimate (e.g. based on playtesting data or a rough calculation) that completing a mission (represented using a moment) will cost the player approximately 50 rounds of ammunition on average. Instead of an average cost, however, you might want to model minimums and maximums or a range, or two different strategies/play styles e.g. an A version, where it’s possible to complete the mission using only 10 rounds, with a B version representing unskilled players who tend to use 80 rounds. Or A might represent a “stealth” strategy and the B version might represent a “combat” strategy.

You can do a kind of A/B test by using automated walkthrough mode (as shown below). See automated walkthrough settings for how this is done.