As an example here are some measurements of the channel interaction.
Chan A fixed to 0, chan B and C varied from 0 - F. Values in volts with 1K load.

AB C=f     e     d     c     b     a     9     8     7     6     5     4     3     2     1     0
0f  3.64  3.50  3.38  3.32  3.29  3.27  3.26  3.26  3.26  3.26  3.26  3.26  3.26  3.26  3.26  3.26
0e        3.33  3.20  3.139 3.083 3.056 3.034 3.019 3.011 3.006 3.003 3.001 3.000 2.999 2.998 2.997
0d              3.06  2.984 2.922 2.890 2.864 2.849 2.837 2.831 2.825 2.822 2.819 2.817 2.815 2.813
0c                    2.904 2.842 2.808 2.781 2.765 2.752 2.744 2.738 2.734 2.731 2.729 2.727 2.724
0b                          2.778 2.743 2.714 2.698 2.683 2.675 2.668 2.664 2.661 2.658 2.656 2.653
0a                                2.708 2.679 2.661 2.647 2.639 2.631 2.627 2.623 2.621 2.618 2.616
09                                      2.649 2.631 2.616 2.607 2.599 2.595 2.591 2.589 2.586 2.583
08                                            2.613 2.598 2.589 2.582 2.577 2.573 2.570 2.568 2.565
07                                                  2.582 2.574 2.566 2.561 2.557 2.555 2.552 2.549
06                                                        2.565 2.557 2.552 2.548 2.546 2.543 2.540
05                                                              2.549 2.545 2.540 2.538 2.535 2.532
04                                                                    2.540 2.536 2.533 2.531 2.527
03                                                                          2.532 2.529 2.526 2.523
02                                                                                2.526 2.524 2.520
01                                                                                      2.521 2.518
00                                                                                            2.515