When you are disputing late charges do you dispute with the CRA or the OC. I always think I have this stuff straight in my head until I start to actually take action.
I'm not sure what exactly you mean when you say "late charges", if you mean "late charges" for fees on your credit card, then these must be disputed directly with the credit card issuer, and should be done in writing. If there was a late payment, and that shows as a "30 day late" on your credit reports, then that must be first disputed with the CRAs. You should also try to dispute with the credit card issuer, again in writing.
These apply in the same manner, any dispute over charges must be done with the lender. If they report "lates" to your credit report, you must dispute with the CRAs first. You can always dispute with the lender, again should be done in writing. You have to careful, if you read the laws of the FCRA, they state that disputes regarding information on your credit report must first be disputed with the credit reporting agencies, otherwise there is no legal ground for the dispute. (i.e. the data furnisher is under no obligation to review your dispute).