Hi JD01234,
Thanks for joining us here on the Community,
Deleting a transaction that has been filed with QuickBooks will create an exception of the filed VAT amount on the open return (you can see these by selecting the drop-down beside Prepare return > View exception details).
When you add a transaction into QuickBooks with VAT that is dated prior to the start date of the open return, this will again create an exception of the VAT amount, meaning if you delete add the invoice back in with the same amount of VAT the overall net impact to your exceptions will be zero.
Please get back to us below if you have any questions!