Contract Amount Sales Tax and WIP

Good afternoon,

We are a contractor charging tax on jobs.   We have been including sales tax in the job estimate.   The problem that has arose is WIP - Job Invoiced to Date doesn't reconcile to the "Revised Contract Amount" because of the sales tax.   I assume there is a different way we should be handling the input of the estimate in Sage?   The sales tax is working correctly on the balance sheet and going in and out when paid.   Or do we need to change the way the WIP report is written?

We appreciate your help.