Charged-off accounts are, by definition, closed accounts, and thus do not represent currently available credit. So i dont see that deletion of non-existing credit would equate to any loss of credit.
As for the continued presence of a CO in your CR, even if paid, a condition of a charge-off when used to write off the collectible asset as a loss under the tax code is that the party declares the debt to have reached the point of being "uncollectible." Later payment does not erase that prior conclusion by the creditor.
That is a very serious negative statement about your credit worthiness that is viewed very unfavorably by others when reviewing your CR.
As for your score, FICO still scores the negative impact of a CO, even if paid, and removal of its effect on your score is only achieved by deletion of the CO. If you want deletion prior to the normal 7 years plus six months from your DOFD with the OC, you must pursue a good-will request. It will effect both your current and future score until deleted. If you pursue deletion, you should not ask for deletion of the account. Just deletion of the CO. That retains the account in your scoring of age of accounts.
Starting Score (08/11/11): TU08: 643