amending 2023 1040 using TT

I Need to amend my 2023 1040 to correct capital gains, but TT will not accept my change of an incorrect K-1 received from a trust. Does this mean I need to make the change in the original TT 1040 rather on the TT 1040x page? I filed the 1040 on time and received my refund.

I assume I will have to pay an additional tax, but wonder how a penalty/interest will be calculated. Does the IRS account for my original refund. Does IRS calculate interest from the date of my amendment submittal or original submittal?

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