Thank you @BillM223 for your quick reply!
I went ahead and copied my return to a test file and tried importing it without deleting anything. I tried this because I discovered I was wrong, and the package ID and Document ID were identical! I wrote down all the values of income categories, and then imported. The changes matched the summary page of changes I had on paper. I also verified there was only 1 1099-B, -DIV, and -INT in my TT file - so everything worked out fine, TT figured it out!
At least that worked in this case - where the package/document IDs let TT know it was a duplicate. I can see where if it has no way to know, it would import a second copy. Good to know!
Thanks again!
