Question about blue dice and defence

[HyveMynd]

Apologies if this has been asked or answered elsewhere. I've been through the latest version of the rules multiple times now, and I simply cannot seem to find the answer.

How do you calculate damage and what do blue defence dice do?

In MF0:RA you compare the value of the attacker's red (or white) die to the target's blue (or white) die. The difference between those two values dictates how many damage dice the attacker rolls, with 4s, 5s, or 6s doing damage to the defender depending on the situation.

Is this how things work in MF0:IO as well? I'm asking because that does not appear to be what the latest round of draft rules say. Currently there is nothing telling players to compare the value of the attacker's red die to the defender's blue die. The rules just say that weapons do damage on 4s, 5s, or 6s depending on the range and situation. Yet we're told to roll and assign blue defence dice (if we have them), which doesn't make sense. Why do we need to assign a die to defence if the value of that die has no effect?

Am I missing something?

[Mantisking]

[HyveMynd]