Account being reported as charge off..need explanation please

I've been reading a few post where some you say that having an account reported as "Charge off" is not good for your credit score. Is this correct?
Well, my credit union, whom I had a car loan with, is reporting the voluntarly repo (I didn't wanna reaffirm the car) as a charge off. Is it normal for a car loan to be reported this way, or should they be reporting as BK?

They should, but are not required to until you have been discharged. If you have already been discharged, you can dispute it with the credit bureau.

I was discharged and I called the creditor. they told me I should first dispute it with the bureaus and then file a dispute with them.