Never change the Estimate if you use Progress Invoicing. That throws everything off-balance.
"I am using desktop pro 2018"
Only Contractor and Accountant have Change Orders. None of the info provided applies to you, the Pro User. What you do is make a New Subjob and a new Estimate for the expanded scope, as Change Order. Then you track and charge on that level for that new scope.
Please see my attachment,