Apologies... I must not have stated clearly. Added Sch SE background simply to say I understand the particulars of the form and calculation so it was not necessary for commenting on the ins/outs of that form. The Schedule SE on ProSeries makes most of the calculations.

The end of my message states there is a refund of $1,240.00  (true reader does not have all my numbers of Sch C Net Profit and W-2 Wages) that the taxpayer overpaid when considering the Original Sch SE is calculated compared to Form 1040X Schedule SE with adding the missed W-2.

Questions:  Able to make this type of situation Schedule SE Self Employment Income with one W2 a refund based on the tax return (Form 1040X) or use Form 843?

Thank you in advance!