I tried going to QB help and the person quit the help session w/o any notice. So....
We are a consulting firm.  We give customers estimates.  They accept.  Employees enter time and select the Customer:Project when reporting their time.

The issue happens when we go to create the invoice.  We need the employees time (which already includes a billable rate) to be subtracted from the estimate.  We need this for tracking how much is left on the estimate each month.

I add the employees' entries to the invoice because it has a description of work performed, which is mandatory to ensure the time we are billing is legitimate.  But adding the time by line doesn't impact the estimate remaining amounts.

We are on Quickbooks Plus - Subscription.