With such metric, you don't make any difference between a 56K telephone line and a 10Ge NIC.
If you 10Ge has 5pc packet loss and your 56K line has 0pc, your TQ will be prefer the 56k link.
If my 10Ge has 5% packet loss, its broken. I don't want to use it. Falling back to the 56K link is the right thing to do.
There is a general rule of thumb. The higher the bandwidth, the less packet loss there is. This is because high bandwidth links are generally not wireless and so don't suffer high packet loss.
As a side effect, BATMAN will tend to favor wired links over wireless links, because wired links tend to be reliable, wireless links drop packets.
Andrew