After I select only those newly-added contractors per your instruction, are you referring that selection in step 7?  "Mark the tick box of all the vendors you want to include."?

The issue is after your Step 9- I click on "Finish preparing 1099s", "E-file for me", I'm redirected to a site "Intuit 1099 E-File Service".  There, I do not see the additional contractor I want to include.  Just the one I've submitted in the past.