The 7,977 gain for Biden is a NET figure.
Of the 61,367 ostensibly still out, Trump would get 26,695. Biden would get 34,672.
The difference is a 7,977 gain for Biden from this. That is less than Trump’s current 13,539 lead.
Theoretically, Trump would win by 5,562.
Are you assuming more boxes of ballots will not be found?