POE 2 - Rarity (From Items) not Calculated Correctly

I strongly believe that the Rarity (From Items) in POE2 is not calculated correctly.

And I just want to ask one of the Dev's to confirm my suspicion and prove me wrong please.

I've been playing the new Dawn of the Hunt and just finished the Campaign and for more that half of the time I've been playing with over 70% Rarity from my Items.

But I've only received poor currency drops from monsters.
Where as a fried of mine with 0% Rarity from his gear has picked up much more currency (Exalted Orbs) from just Campaign play.

Now this could be by chance. but still something does not feel right.

Why do I say that.

When calculating Rarity. (simplified) you would.

Total Rarity = Base + Total Item Rarity * Constant;

where the "Base" is when you have no rarity so let's give that a value of 1;
"Total Item Rarity" is your total Item Rarity so lets use mine of 70%
And the Constant can be anything so lets use 100;

Now Total Rarity = 1 + 0.7 * 100 = 170;
you would think this is correct but it is not.

the math will not work out like you would expect, it will be

Now Total Rarity = 1 + (0.7 * 100) = 71
Because of the "Order of arithmetic operator execution"
I will now have less "Rarity" than my friend, who will have.

Now Total Rarity = 1 + _ * 100 = 100 (not using the Item rarity value be cause there isn't any so it's just 1 * 100)

This is also why in the first Standard League only people who have over 101% rarity finally saw from better loot drop.

Example: of a 230% total gear rarity

Total Rarity = 1 + 2.3 * 100 = 231

Where it should have been.

Total Rarity = (1 + 0.7) * 100 = 170
and
Total Rarity = (1 + 2.3) * 100 = 330
(yes 330 is correct because it's the base 100 + the total gear)
you could also calculate it like this.

Total Rarity = (Base * Constant) + (Total Item Rarity * Constant);

Total Rarity = (1 * 100) + (0 * 100) = 100 (no rarity)
Total Rarity = (1 * 100) + (0.7 * 100) = 170 (70% rarity from items)
Total Rarity = (1 * 100) + (2.3 * 100) = 330 (230% rarity from items)

do not penalise players who are trying to add Rarity to their gear and not getting the reward they work hard for.