The different versions arise from multiverse considerations. The obvious basic route to sim capture is recreating very close copies that experience everything we remember having experienced - a recreation of our exact specific historical timeline/branch.

But even recreating other versions corresponding to other nearby branches in the multiverse could work and is potentially more computationally efficient. The net effect is the same: it raises the probabillity that we exist in a sim created by some other version/branch.

So there are two notions of historical 'accuracy'. The first being accuracy in terms of exact match with a specific timeline, the other being accuracy in terms of matching only samples from the overall multiverse distribution.

Success only requires a high total probability that we are in a sim. It doesn't matter much which specific historical timeline creates the sim.

The idea of decision agreement still applies across different versions in the multiverse. It doesn't require exact agreement with every micro decision, only general agreement on the key decisions involving sim creation.