Well, the difference between the proper withholding amounts is ~$4612. IF that $ amount appears on line 17 of the form 1040, then I would suspect that you double entered that amount.
Though we may not yet have all the information needed.....the key here may be the entry you see on line 18a on the Tax Payments worksheet. That value can only be entered by the user in an interview section for "Withholding"...that is not entered elsewhere on some W-2 or 1099 type of form. The line 18 value adds into all your other Federal "withholding" for line 16 of the form 1040.
BUT...Withholding is not the same thing as an Estimated tax payment. They are treated and enumerated as separate items.
IF you accidentally entered any or all of your "Estimated" payments in that "withholding" part of the interview, and then also entered the same amount (properly) as one or more quarterly "Estimated" payments, then that is a double entry you may have accidentally made.
The Estimated payments line (line 66 on the 2018 schedule 5) can also include a prior year refund...from 2017 taxes (the IRS also considers/enumerates that as an "estimated" tax payment) . If you only have the line 66 entry on that schedule 5 then that same amount (total on line 75) feeds into line 17 of the 1040.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
