The reporting of a charge-off is basically their statement that you were previously determined to be a consumer who is not going to pay their debt.
They then are able to recoup a portion of the uncollectible debt based on that determination.
While ultimate payment of the debt does help to mitigate that prior perception, they nonetheless may still have a negative perception.
Additionally, "undoing" the CO essentially requires that your payment be declared as a received asset, thus negating their prior writeoff and tax benefit when they shfited your previously receivable asset to a non-receivable bad debt. They thus have a net of less than the full amount of the debt.
Hard to overcome those negatives.
The best argument that I can suggest in requesting deletion of a reported CO is that, while it may have appeared at the time, based on the lenghty period of delinquency, that you were unlikely to pay the debt, your act of paying the debt shows that you honor your obligations, and that deletion of the CO would more accurately reflect upon you as a consumer.
