Changes is how many DISTINCT regimes may be adopted per Window. A restatement identical to the regime in force mints no version and is not counted against it.
Disposed is how many versions retention has taken. It is NOT a silence: a history bounded on disk must say what it no longer holds, because a decision citing a disposed version can no longer be reconstructed from this record.
Version is the version in force — the one every score currently cites. Zero means no regime has ever been stated and the default posture, shadow, is in force.