Channeling + Invoking = Immunity, How does this interact with your armor? Options

[Apathy]

Ok, say your a combat mage initiate wearing FFBA3 (4/1) and an Armored Jacket (5/3). Your base armor is now 7/4.

Now you summon a force 4 city spirit, invoke it, and channel it. This gives you immunity to normal weapons at the spirit's force (4), effectively giving you 8/8 hardened armor.

The question is, how does this 8/8 work with the 7/4 armor you got from your normal clothes? If the immunity effectively makes your skin harder, then you'd be able to reduce the overall power of weapons by your armor's rating before comparing it to your immunity to see if you're affected.

Example: Sam the Samari draws his Ranger-X bow (set for strength min = 10) and put an arrow dead-center on your chest doing 14M. I think it would work like this:

1. The arrow first hit your Jacket and FFBA, which slow it down (reducing the power of the attack by 7 down to 7M).
2. You compare the adjusted power of the attack (7) with the level of your immunity (8/8 ). In this case, the attack wasn't quite strong enough, and the arrow bounces harmlessly off the mage's chest.

Is this how you'd do it?