When you click on the option to data append you will see an estimate of how many matches we expect historically to be matched as well as what the estimated cost is.
The data Append Estimator is one of the steps in the data append process.
It will look at the size of the farm and estimate how many matches we will get based on historical match rates for email and phone.
We will then let the Agent know that it will be approximately $XX.XX to perform the data append. You will only be charged for matched data. The rest is converted into a credit and attached to your account for use on future data optimizations or refreshes.