Amendment refund input please!!!

So I missed one of my husbands W-2's while filing this year and when I went back to amend our return and add it, the refund amounts seem strange. Just curious if anyone has any insight?
Original filing was State:1488 refund, Fed:402 owed.
Amended says State:1431 refund, Fed:187 owed.
TT FAQ says the amended numbers are unrelated to the original ones, that seems not right to me. Thoughts?