Hi Gerri - welcome to the site
I dont think you can request a reduced settlement but I guess it doesnt hurt to try - usually with a reduced settlement they want you to pay in one lump sum.
Who did you agree to the payment plan with ? Cap One & BArclay card direct ? Is it a sensible payment plan (ie. can you afford to keep paying it )
Re the charges you had applied to the accounts you could claim these back.... although you might risk losing the frozen interest on the plan ? Do you have an idea of how much the charges are in relation to the debts ?
If you give a bit more info then hopefully someone with more knowledge in this area will find you.