There is a ratebook for Centracom. For CentraCom ratebook refer to forum post -
Where do I find CentraCom ratebook?Once the Centracom ratebook is in place and the costing changes, then you can do the rates adjustment using the TNG Custom rates feature - see forum post -
Zones to use for TNG and Custom rates. TNG has the custom ratebook feature so that the client can do rates adjustments. Some service providers have rates discounts per clients and also make rates changes per customer, etc. - therefore a general ratebook for the provider cannot cater for this as it is client specific, etc.
To change the rate books, I have to refer you to previous discussion see forum post:
Re: TNG RATES UPDATES FOR CENTRACOM RATES