Two Shapes That Only Match After a Flip

A layer stores its parameters as a $3 \times 4$ matrix $A$, while a second bank of numbers arrives from a different source already laid out as a $4 \times 3$ matrix $B$:

$A = \begin{bmatrix} 3 & -1 & 4 & 2 \\ 0 & 5 & -2 & 6 \\ 7 & 1 & -3 & 8 \end{bmatrix}, \qquad B = \begin{bmatrix} 2 & -4 & 1 \\ 5 & 0 & -2 \\ -1 & 3 & 6 \\ 4 & 2 & -5 \end{bmatrix}$

Form the matrix

$C = 2A^{T} - 3B$

Rows and columns are numbered starting at $1$. Report

$(\text{total of row } 3 \text{ of } C) - (\text{total of column } 1 \text{ of } C)$

Give your answer as an exact whole number. It may be negative.