how to setup the plugin

Hello,
I didn’t understand how to do to setup the plugin…
I actually have 2 different classes (one type of product uses class A and the other type uses class B).
Now, based on that, I have different costs, for each class, based on weight and zip code.
I already created the different regions based on zip codes.
But now, I don’t know how to do ti setup APG for the different weights.
Here’s what I tried:

4|10|classa
8|20|classa
12|30|classa
4|140|classb
8|150|classb
12|220|classb

Here I tried to do:
For products <= 4Kg, for class a, the price will be 10 euros.
For products <= 8Kg, for class a, the price will be 20 euros.
For products <= 12Kg, for class a, the price will be 30 euros.
For products <= 4Kg, for class b, the price will be 140 euros.
For products <= 8Kg, for class b, the price will be 150 euros.
For products <= 12Kg, for class b, the price will be 220 euros.

But it’s not working…
I tried with a class A product, of 10.2 Kg (should trigger 30 euros), and it shows 170 euros…
I don’t understand.
Could you please help me ?

Thanks a lot