Well, we (me and my opponent) are not native language speaker, so we have a different interpretation of the rules. So I understand it is not sequential (unless ambush occurs, understood), but the Attacker attack in CC and then withdraw, without being attacked. Thanks for the clarification.
In "simultaneous" CC when a player rolls snakeeyes on an attack, the units may
immediately withdraw, regardless of whether they creates a leader or not, and regardless of whether or not they eliminated their target, unless the units have already been eliminated. Despite being called "simultaneous" CC the game mechanics are anything but. The ATTACKER announces all his attacks, then the DEFENDER. The ATTACKER next makes all his DRs, then the DEFENDER.
In a simple example, assume two four-FP squads are attacking each other, and the CC is not sequential. The ATTACKER announces a 1:1 attack. The DEFENDER announces a 1:1 attack. No surprises there.
The ATTACKER now rolls his attack. If he rolls a two, he rolls for leader creation, and after that is figured out, he determines the effect of the attack. It is possible that even with a two he does not eliminate the target. He might be CX in crest status and just created a 6+1 leader, in which case there is no result. Because the squad (and any newly-created leader) rolled a two, it may withdraw immediately. If the squad withdraws the DEFENDER will have no attack back. If the ATTACKER does not withdraw, the DEFENDER will have its attack back, possibly now at 1:2 odds because of a new leader. If the ATTACKER squad does not roll a two, it may still eliminate or CR the DEFENDER.
The DEFENDER now rolls its 1:1 attack (assuming the ATTACKER did not roll a two and withdraw). It too may roll a two. If it does, it rolls for leader creation and refigures its attack if a leader is created. Again the DEFENDER may or may not eliminate the ATTACKER with a two, depending on DRM. Regardless of whether the ATTACKER is eliminated or not, the DEFENDER squad may withdraw unless it was eliminated by the ATTACKER in the preceding step. If it was CR'd the surviving halfsquad may withdraw.
JR