OK, fair enough
To this same point, I buy 95% one way fares as changing the second half of a RT ticket is a GIANT PITA, even a refundable fare is horrid cause you never know what your residual will be, and I typically have to change it several times and SDC really isn't feasible as I may have to change destinations most times.
But that chart is typically pretty close for what the airlines give me for residual value after flying half the ticket