How is 1% chargeback calculated?
 

I have a merchant account and use Netbilling as a gateway for one of my non-adult membership site ventures. I know about the 1% but I am wondering if it is counted as a chargeback if after investigation it turns out

1) Was a fraudulent transaction or error on a credit card companies mistake.
2) After contesting I get the chargeback reversed.
3) They chargeback after we have already issued a refund.
4) The bank somehow proves the person did in fact make the charge.

I've asked my bank and others and keep getting different answers also do they count both the Trial and the Rebill as two separate transactions when calculating this percentage?

Thanks