Solo CoX: Olm Changing Attack Tick

I've been using the visual metronome plugin (set to 4) to learn how to solo Olm (thank you VideoGameBot). When I enter the room I figure out what tick he attacks on (say for example: tick 2), which is the tick I have to attack on for 3:0 on the mage hand, and also 1:0 melee hand (still learning 4:1). I've seen that Olm's attack tick typically increments by 2 each time you kill both hands. So on the first round of hands I attack on 2, then on the next round I would attack on 2+2 = 4, then in the final round I go back to attacking on 2.

My problem: sometimes this isn't the case. Sometimes he won't increment to a different tick on the second or third round, so instead of 2-4-2, it will be something like 2-2-4. Is this predictable? Am I doing something wrong? Is this server lag? Am I going crazy?

Thanks!