Yes, RR points have always held (slightly) different values for different fares because of how they're calculated. Thus, people who insist that RR points have some sort of fixed value are off-base.

Here's an example. I have three future one-way flights booked between CMH and the DC area. I am going to cancel one of these flights and pay cash instead for it. Which one should I cancel?

CMH-BWI $83 WGA fare 4,428 points
BWI-CMH $94 WGA fare 5,144 points
IAD-MDW-CMH (direct) $98 WGA fare 5,144 points

The first flight, if I cancelled it and paid cash, I would effectively be buying points at 1.874 cents per point. The second flight, 1.827 cents per point. The third flight, 1.905 cents per point. Thus, I will be "buying" points at the best value by cancelling the second flight, the BWI-CMH non-stop.

The values vary even more than that. A CMH-LGA flight is $165 cash or 9,246 points, making those points worth 1.784 cents apiece.

If one factors in the points you would receive by switching a points reservation to cash, the cost per point reduces dramatically. In my BWI-CMH example above, I would "get" the 5,144 points back, but I'd also get about 400-450 points on top of that for paying cash (and not paying the $5.60 fee, but whatever).