Bob,

Form 1310, Part 1, Box B is very misleading, so I understand your confusion. But when you read Form 1310 instructions carefully, Part 1, Box B is only applicable when involving one of these two situations:

1) Form 1040X, Amended U.S. Individual Income Tax Return, or

2) Form 843, Claim for Refund and Request for Abatement. 

Below is the paragraph pulled directly from Form 1310 instructions:

Check the box on line B only if you are the decedent’s court-appointed or certified personal representative claiming a refund for the decedent on Form 1040X (1040-X beginning with the
January 2020 revision), Amended U.S. Individual Income Tax Return; or Form 843, Claim for Refund and Request for Abatement. You must attach a copy of the court certificate showing your appointment. But if you have already sent the court certificate to the IRS, complete Form 1310 and write “Certificate Previously Filed” at the bottom of the form.